JP2011189639A - Transfer adjusting method of printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve printing quality by maintaining constant a feed amount of recording paper independently of types of recording paper and factors changed with time such as change of an amount of abrasion of rollers and an amount of paper dust adhered to rollers in a printer which includes a transfer roller pair driven by a motor for transfer of the recording paper and a printing unit which carries out printing to the recording papers transferred by the transfer roller pair. <P>SOLUTION: An amount of gap between the number of command pulses of the motor necessary for transferring a reference recording paper and the number of command pulses of the motor necessary for transferring recording paper other than the reference recording paper is stored beforehand as correction table data for each type of recording paper. Moreover, an amount of gap of the number of command pulses of the motor necessary when the reference recording paper is transferred at the present time point from a shipping time point of the printer is acquired by measurement. A command pulse number of the motor is set according to the type of the recording paper on the basis of the acquired amount of gap and the correction table data (step S9). <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention belongs to a technical field related to a conveyance adjustment method for a printer including a conveyance mechanism for conveying a recording sheet and a printing unit that performs printing on the recording sheet conveyed by the conveyance mechanism.

  2. Description of the Related Art Conventionally, printers that include a transport mechanism that transports recording paper at a preset feed amount and a printing unit that performs printing on the recording paper transported by the transport mechanism are known (for example, patents). Reference 1 and 2). In these printers, a conveyance roller pair including a driving roller and a driven roller is provided on the conveyance upstream side and downstream side of the printing unit as a conveyance mechanism, and the recording paper is sandwiched and conveyed by each conveyance roller pair. I have to. The drive roller is usually driven by a servo motor with excellent controllability.

JP 2006-251627 A JP 2004-216651 A

  By the way, in order to improve the print quality in the printer described above, it is necessary to control the feeding amount of the recording paper by the transport mechanism to be constant. For this purpose, it is necessary to suppress the variation in the frictional resistance between the recording paper and the roller as well as to improve the rotation accuracy of the driving roller using the servo motor as described above. This frictional resistance changes depending on temporal factors such as the degree of roller wear and the change in the amount of paper dust adhering to the roller surface. For this reason, for example, even when the control value of the motor is set so that the recording paper feed amount by the transport mechanism becomes the set feed amount when the printer is shipped from the factory, subsequent roller wear and paper dust There is a problem that the feeding amount of the recording paper deviates from the set feeding amount due to the occurrence.

  In recent years, with the diversification of customer needs, the ability to execute printing on a plurality of types of recording papers of different materials and sizes is required for a single printer. In such a printer, the frictional resistance between the roller and the recording paper changes depending on the type of the recording paper, and therefore there is a problem that the feeding amount of the recording paper cannot be maintained at the set feeding amount regardless of the type.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a transport mechanism for transporting recording paper and a printing unit that performs printing on the recording paper transported by the transport mechanism. In a printer equipped with the above, by adjusting the transport adjustment method, the recording paper is not affected by time-dependent factors such as the type of recording paper and changes in the amount of roller wear and the amount of paper dust adhering to the roller. In other words, the printing amount of the recording paper is to be improved by keeping the feeding amount constant.

  In order to achieve the above object, according to the present invention, a necessary drive amount of a transport mechanism necessary for transporting the reference recording paper and a transport mechanism necessary for transporting recording paper other than the reference recording paper are required. A value indicating the amount of deviation from the drive amount is stored in advance as a correction table for each type of recording paper, and further, from a predetermined point in time of the required drive amount of the transport mechanism necessary for transporting the reference recording paper at the present time. A value related to the amount of deviation is measured, and based on the measured value and the correction table, the driving amount of the transport mechanism is controlled according to the type of recording paper.

  According to the first aspect of the present invention, a plurality of types of recording are provided, comprising a transport mechanism for transporting the recording paper at a preset set feed amount, and a printing section for printing on the recording paper transported by the transport mechanism. The present invention is directed to a conveyance adjustment method of a printer configured to be able to print on paper.

  And a type detecting step for detecting a type of recording paper to be printed by the printing unit, and a necessary driving of a transport mechanism necessary for transporting a predetermined type of reference recording paper by the set feed amount at a predetermined time. A value indicating the amount of deviation between the amount and the required drive amount of the transport mechanism necessary for transporting the recording paper other than the reference recording paper by the set feed amount, and obtaining the obtained value of the recording paper A data storage step for storing the correction data for each type in advance, and a deviation amount from the predetermined time point of the required drive amount of the conveyance mechanism necessary for conveying the reference recording paper by the set feed amount at the present time Based on the type of recording paper detected in the type detection step based on the measurement step for measuring the relevant value, the correction data stored in the data storage step, and the value measured in the measurement step The recording paper As the feed amount becomes the set feed amount, and include at a control step of controlling the drive amount of the conveyance mechanism.

  According to this method, based on the correction data stored in the data storage step, the drive amount of the transport mechanism is controlled according to the type of recording paper, so that the feeding amount of the recording paper can be controlled regardless of the type of recording paper. It can be controlled to the set feed amount. Therefore, even if there is a difference in the conveyance resistance (friction resistance) because the type (size, material, etc.) of the recording paper to be printed is different, the recording paper feed amount can be kept constant, and the printed image can be maintained. Image quality can be improved.

In the present invention, a value related to a deviation amount between the required drive amount of the transport mechanism at a predetermined time (for example, at the time of factory shipment) and the required drive amount of the transport mechanism at the present time is measured, and based on the measured value. By controlling the drive amount of the transport mechanism, the recording paper feed amount is kept constant even if the transport resistance of the recording paper changes due to temporal factors such as wear of the transport mechanism and changes in the amount of paper dust. be able to. Therefore, the image quality of the printed image can be further improved. Here, the “value related to the deviation amount” can be a deviation amount of the recording paper conveyance amount when the recording paper is conveyed with the same driving amount of the conveyance mechanism at a predetermined time point and the current time point, for example. In the invention of item 2, in the invention of claim 1, the printing unit is configured to perform printing on the back side surface after printing on the front side surface of the recording paper, and printing is performed on the printing unit. It further includes a front / back determination step for determining whether the printing surface of the recording paper to be performed is the front side or the back side, and the data storage step is configured to transfer the reference recording paper by the transport mechanism at the predetermined time. When transporting so that the back side is the printing surface, when recording paper other than the reference recording paper is transported so that the front side is the printing surface, and so that the recording side is the printing side Required for each case when transported to A value indicating a deviation amount between the required drive amount of the transport mechanism and the required drive amount of the transport mechanism that is necessary when the reference recording sheet is transported so that the front side surface thereof becomes a printing surface at the predetermined time point. This is a step of acquiring and storing the correction data as the correction data, and the measurement step requires a transport mechanism necessary for transporting the reference recording paper at the present time by the set feed amount using the front side as a printing surface. A step of measuring a value related to a deviation amount of the drive amount from the predetermined time point, wherein the control step is based on the correction data stored in the data storage unit and the value measured in the measurement step. In addition, according to the type of the recording paper detected in the type detection step, and further according to the determination result in the front / back determination step, the conveyance amount of the recording paper is set to the set feeding amount. Drive of mechanism It is assumed that a step of controlling the amount.

  According to this method, based on the correction data, not only the type of recording paper but also the printing surface of the recording paper controls the driving amount of the transport mechanism according to either the front side or the back side, Even if the stiffness or curving characteristic (curl) of the recording paper changes between the front surface printing and the back surface printing of the recording paper, the recording paper feed amount can be maintained at the set feed amount.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the transport mechanism includes at least one pair of transport rollers that sandwich and transport the recording paper between a driving roller and a driven roller, and the control step includes In this step, the rotation amount of the driving roller is controlled as the driving amount of the transport mechanism.

  According to this method, even if each roller constituting each conveyance roller pair is worn or paper dust adheres to the surface of each roller, the conveyance resistance between each roller and the recording paper changes. By controlling the rotation amount of the drive roller based on the correction data stored in the storage step and the value measured in the measurement step, the recording paper feed amount can be controlled to the set feed amount. .

  As described above, according to the conveyance adjustment method of the printer of the present invention, the necessary drive amount of the conveyance mechanism necessary for conveying the reference recording sheet and the necessary amount for conveying the recording sheet other than the reference recording sheet. A value indicating the amount of deviation from the required drive amount of the transport mechanism is stored in advance as a correction table for each type of recording paper, and further, the required drive amount of the transport mechanism required when transporting the reference recording paper at the present time By measuring a value related to the amount of deviation from a predetermined point of time, and based on the measured value and the correction table, the drive amount of the transport mechanism is controlled according to the type of recording paper, Regardless of factors such as changes in the amount of roller wear and the amount of paper dust adhering to the roller, and the type of recording paper, the amount of recording paper fed can be kept constant, and printing of recording paper is possible. Quality can be improved.

1 is a perspective view illustrating an appearance of an ink jet printer according to an embodiment of the present invention. It is the schematic seen from the side which shows the internal structure of an inkjet printer. It is sectional drawing which shows the detail of the inside of a cassette. It is a side view which shows the detail of a printing part and a U-turn part. It is a top view which shows the detail of a printing part. FIG. 6 is a schematic diagram illustrating a state in which a switchback roller pair of a switchback unit receives a recording sheet conveyed from a reverse conveyance unit. FIG. 7 is a view corresponding to FIG. 6 showing a state in which the driven rollers of the switchback roller pair are switched to the second position. FIG. 7 is a view corresponding to FIG. 6 illustrating a state in which the switchback roller pair switches back the recording paper to the supply roller pair. FIG. 7 is a view corresponding to FIG. 6 showing a state in which the recording paper is manually inserted from the manual insertion opening. FIG. 3 is a view corresponding to FIG. 2 showing a state in which the duplex printing unit is removed from the printer body. It is a conceptual diagram which shows the structure of a printing conveyance mechanism. It is the perspective view which showed the printing part and the printing conveyance part periphery. It is a side view which shows the principal part of a printing conveyance part. FIG. 10 is a diagram for explaining the operation of the first and second transport roller pairs during execution of the step-change control in the transport control unit, and (a) transports the recording paper with only the first transport roller pair in a pressure-bonded state. (B) shows the state immediately before switching the first conveying roller pair to the non-crimping state and the second conveying roller pair to the crimping state. (C) shows only the second conveying roller pair after the switching. A state in which recording paper is conveyed as a state is shown. FIG. 2 is a block diagram illustrating a configuration of a printer control system. It is a figure which shows the screen displayed on the liquid crystal monitor of a reception block, (a) shows a mode selection screen, (b) shows a correction value input screen. (A) shows correction table data stored in the ROM when the printer is shipped, and (b) summarizes materials and sizes of various recording papers of the reference recording paper, the first recording paper, and the second recording paper. It is a table. 6 is a flowchart illustrating print control in a print control unit. FIG. 7A is a diagram illustrating a state of setting printing executed by the print control unit, FIG. 10A is a print image that has been processed in the first half of setting printing, and FIG. 5B is a process in the latter half of setting printing. Is a print image that has been finished.

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

-About the overall structure of the printer-
FIG. 1 shows an external appearance of an inkjet printer A according to an embodiment of the present invention, and FIG. 2 schematically shows an internal configuration of the inkjet printer A. The inkjet printer A is used in a photo print system. For example, the inkjet printer A acquires image data and order information and performs necessary correction processing from a reception block 200 (see FIG. 15) via a communication cable. The image data transmitted in this manner is printed on the recording paper P based on the order information. Here, the inkjet printer A has a normal print mode based on the image data from the reception block described above and a test print mode for test printing, and the user can select which mode is used for printing. It has become. The recording paper P to be printed is a cut paper cut to a predetermined size, and a plurality of types (see FIG. 17B) are preset as the sizes.

  The ink jet printer A includes a printer main body 1 having a casing 2 with a caster 3 provided on the lower surface thereof, and a detachably attached upper portion of one side of the casing 2 of the printer main body 1 and a plurality of recordings. A cassette 5 that can store paper P in the thickness direction and a duplex printing unit 7 that is detachably attached to the upper surface of the housing 2 are provided. In the present embodiment, the side on which the cassette 5 is attached (left side in FIG. 2) is referred to as the printer front side, and the opposite side (right side in FIG. 2) is referred to as the printer rear side. Also, the direction perpendicular to the paper surface of FIG. 2 is the left-right direction of the printer, and coincides with the width direction of the recording paper P accommodated in the cassette 5 and conveyed in the printer main body 1 and the duplex printing unit 7. .

  As shown in FIG. 2, in a state where the double-sided printing unit 7 is attached to the printer main body 1, it is possible to print on both the front and back sides of the recording paper P as will be described in detail later. On the other hand, when printing is performed only on one side of the recording paper P and double-sided printing is not required, the double-sided printing unit 7 is usually removed from the printer body 1 (see FIG. 10). However, even when the duplex printing unit 7 is attached to the printer main body 1, it is possible to print on only one side of the recording paper P. By bundling a plurality of recording papers P printed on both sides, a photo album or a photo book can be produced.

  The cassette 5 differs depending on the size of the recording paper P. When the user attaches the cassette 5 to the printer main body 1, the type of the recording paper P corresponding to the cassette 5 (FIG. 17B). )) Is input by an operation switch (not shown). For example, an IC chip is provided in the cassette 5, and the size of the recording paper P is stored in the IC chip. When the cassette 5 is attached, the printer main body 1 stores the IC chip. The contents may be read. In this way, the user's input work becomes unnecessary.

  As shown in detail in FIG. 3, a set tray 11 for setting the recording paper P in a state of being stacked in the thickness direction is disposed in the cassette 5. The set tray 11 is supported in the cassette 5 so as to be rotatable about a shaft 11a extending in the left-right direction of the printer at a substantially center of the set tray 11 in the front-rear direction of the printer. The set tray 11 is biased by a spring so that the rear end of the printer rotates to the ascending side. As a result, the uppermost recording paper P among the plurality of recording papers P set on the set tray 11 comes into contact with the feeding roller 14 disposed at the upper part of the rear end of the printer in the cassette 5. It will be.

  The feeding roller 14 is driven in a counterclockwise direction in FIG. 3 by a motor (not shown) disposed on the printer main body 1 side, and the feeding roller 14 is rotationally driven by this motor. As a result, only one uppermost recording sheet P is moved to the rear side of the printer and fed out of the cassette 5. At this time, in order to prevent the recording sheet P positioned below the uppermost recording sheet P from being dragged by the uppermost recording sheet P and simultaneously feeding a plurality of recording sheets P to the outside of the cassette 5. When the feed roller 14 is rotated by a predetermined amount, the tray pressing mechanism 16 lowers the rear end of the set tray 11 on the printer.

  The tray pressing mechanism 16 includes a tray pressing lever 17 supported on the printer body 1 so as to be rotatable about a shaft 17a extending in the left-right direction of the printer, and the tray pressing lever 16 is rotated around the shaft 17a. And a lever rotating cam 18 for moving the lever. The lever rotating cam 18 is rotated around a shaft 18a by a motor (not shown). One end of the tray push-down lever 17 enters the cassette 5 so as to be positioned above the rear end of the printer on the set tray 11 when the cassette 5 is attached to the printer main body 1. On the other hand, the other end of the tray pressing lever 17 is in contact with the cam surface of the lever rotating cam 18. In order to always maintain this contact state, the tray pressing lever 17 is urged by a spring so that the other end portion moves toward the lever rotating cam 18 (that is, one end portion moves upward). Has been.

  When the feed roller 14 is rotated by a predetermined amount, the lever rotating cam 18 is rotated so that the one end portion of the tray pressing lever 17 comes into contact with the rear end portion of the set tray 11 on the printer side. Press this down. As a result, the recording paper P positioned below the uppermost recording paper P is prevented from being dragged by the uppermost recording paper P, and a plurality of recording papers P are not simultaneously fed out of the cassette 5. When the lever rotating cam 18 is rotated halfway, the one end portion of the tray pressing lever 17 starts to rise, and accordingly, the rear end of the printer of the set tray 11 is raised by the spring, and then the most The upper recording paper P contacts the feed roller 14. When the lever rotation cam 18 makes one rotation, the rotation of the lever rotation cam 18 stops and the tray pressing lever 17 returns to the initial state.

  The recording paper P delivered to the outside of the cassette 5 by the delivery roller 14 is supplied to a printing unit 21 described later in the printer body 1.

  A printing unit 21 that performs printing based on the image data is provided in the vicinity of the mounting portion of the cassette 5 in the upper part of the housing 2 of the printer main body 1. As shown in detail in FIGS. 4 and 5, the printing unit 21 includes a print head H that prints on one side of the recording paper P and the recording paper P supplied from the feed roller 14. And a platen 23 that supports the recording paper P conveyed from the print conveyance unit 22.

  A pressure-bonding-type first transport roller pair 24 is disposed at the upstream end of the print transport unit 22 (upstream of the print unit 21 transport), and the downstream end of the print transport unit 22 (of the print unit 21). A pressure-bonding type second conveyance roller pair 25 is disposed on the conveyance downstream side. First and second sensors 27 and 28 (both comprising a light projecting part and a light receiving part) for detecting the recording paper P are disposed on the upstream side and the downstream side of the first conveying roller pair 24, respectively. Has been.

  Details of the print transport unit 22 and the like will be described later separately.

  The print head H is movable along two guide rails 31 extending in the main scanning direction X (see FIG. 5) that coincides with the width direction of the recording paper P (left and right direction of the printer) at the upper position of the recording paper P. It is configured. Further, the print head H has two head units 32 arranged in the sub-scanning direction Y (see FIG. 5) that is perpendicular to the main scanning direction X and coincides with the moving direction of the recording paper P (the front-rear direction of the printer). In addition, a plurality of colors of ink are ejected downward from a large number of ink ejection nozzles (not shown) provided on the lower surfaces of these two head units 32, whereby a predetermined amount is applied to the upper surface of the recording paper P. The image of can be printed. That is, a printing position (a position where an image is printed by landing ink on the recording paper P) is set immediately below each head unit 32 in the conveyance path of the recording paper P. In this embodiment, the head units 32 are arranged in two stages in the sub-scanning direction Y. However, the head units 32 do not have to be two stages, and may be one stage or three stages or more. In the following description, the head unit 32 positioned on the upstream side of conveyance is referred to as an upstream head unit 32, and the head unit 32 positioned on the downstream side of conveyance is referred to as a downstream head unit 32.

  Both the head units 32 have the same configuration, and each has a plurality of nozzle arrays arranged in the main scanning direction X for ejecting ink of each color. In each nozzle array, the ink discharge nozzles are arranged in a row in the sub-scanning direction Y. Thus, each head unit 32 is configured to be able to form a color image by itself. The recording paper P is transported intermittently in the sub-scanning direction Y by the unit transport amount (preset feed amount D) by the first transport roller pair 24 or the second transport roller pair 25, and this intermittent transport. At each stop of the recording paper P at the time, the print head H is scanned one time (one-way operation or one-time operation) in the main scanning direction X, and each head unit 32 at each position in the main scanning direction X during this scanning. Ink is simultaneously ejected from the ink ejection nozzles of the respective colors onto the upper surface of the recording paper P. That is, after one scan of the print head H, the recording paper P is transported by the unit transport amount, and then the print head H is scanned once again, and this operation is repeated to print a desired image. .

  Here, as a configuration for ejecting ink of the print head H in the present embodiment, a general piezo type is adopted.

  The platen 23 is made of a plate-like member, and the upper surface thereof is a support surface 23 a that supports the recording paper P. The platen 23 is provided with a number of suction holes 23b (see FIG. 5) penetrating in the thickness direction (vertical direction) and opening to the support surface 23a.

  The suction holes 23b are arranged in a line along the left-right direction and the front-rear direction of the printer. Specifically, when viewed along the conveyance direction of the recording paper, a group of suction holes 23b, 23b,... (Suction hole group) on the support surface of the platen is substantially orthogonal to the conveyance direction of the recording paper P. The suction holes are arranged in a line in the left-right direction, and a plurality of these suction hole groups are arranged at predetermined intervals in the front-rear direction of the printer.

  A case body 35 (see FIG. 4) that forms a space with the platen 23 is disposed below the platen 23, and a suction device 36 including a fan and the like is disposed below the case body 35. Yes. The suction hole 23b communicates with a space in the case body 35. This space communicates with a suction port of the suction device 36, and the operation of the suction device 36 causes the platen 23 to pass through the suction hole 23b. A negative pressure is generated on the support surface 23 a side, and the recording paper P is sucked and held on the support surface 23 a of the platen 23. Thereby, it becomes possible to ensure the flatness of the recording paper P at the time of printing and to improve the printing quality.

  Further, the support surface 23a of the platen 23 is formed with a recess 23c (see FIG. 5) extending in the sub-scanning direction Y for accommodating the ink absorbing material 38. The ink absorbing member 38 allows a part of the ink ejected from the print head H (head unit 32) to be printed on the recording paper P on the support surface 23a when performing borderless printing for printing an image on the entire recording paper P. This is provided in order to prevent the support surface 23a of the platen 23 from being soiled by the ink that has come off from the outer edge of the width direction. For this reason, the concave portion 23c is located at a position corresponding to the width direction edge of the recording paper P on the support surface 23a and a position corresponding to the print head H in the sub-scanning direction Y on the support surface 23a. (Ie, extending in the sub-scanning direction Y). The ink absorbing material 38 is preferably made of, for example, a sponge having excellent ink absorbability.

  Here, when performing borderless printing, ink is ejected to the edge of the recording paper P in the width direction, and ink protruding from the edge is absorbed by the ink absorber 38. Printing is performed with a predetermined amount (for example, 2 mm) of blank space without ejecting ink at the very front and back edges of the recording paper P. Then, the margin is finished by cutting the margin with a cutter 40 described later. This is because when ink is ejected toward the leading edge or the trailing edge of the recording paper P, the ink is drawn into the suction hole 23b by the suction action by the suction hole 23b, and the print quality is deteriorated. This is because 23a is stained with ink.

  On the downstream side of the print transport unit 22 in the upper part of the casing 2 of the printer main body 1, the recording paper P sent out from the downstream end (second transport roller pair 25) of the print transport unit 22, A U-turn portion 45 is provided for making a U-turn so that the front and back are reversed and the conveyance direction is reversed.

  Between the U-turn part 45 and the print transport part 22, a cutter 40 for cutting the margins at the leading edge and the trailing edge of the recording paper P when the borderless printing is performed is disposed. The cutter 40 is disposed on the upper side of the conveyance path of the recording paper P and the lower side of the conveyance path of the recording paper P, and is vertically moved with respect to the fixed blade 40a by a motor (not shown). The movable blade 40b is moved, and the movable blade 40b moves from the lower side to the upper side of the recording paper P to cut the recording paper P. Chips resulting from this cutting fall and are stored in a waste box 41 (see FIG. 2) disposed in the lower part of the housing 2. When printing on both sides of the recording paper P, the margin is cut by the cutter 40 after printing on both sides.

  The U-turn section 45 is provided with two sets of pressure-conveying rollers disposed on the upstream side of the U-turn section 45 and sandwiching the recording paper P from the print transport section 22 and further transporting it to the rear side of the printer. A pair 46, a first direction changing member 47 for changing the direction of conveyance of the recording paper P conveyed by the conveyance roller pair 46 to the upper side, and a recording medium disposed on the downstream side of the first direction changing member 47 and recording. Two pairs of pressure-conveying conveyance rollers 48 that sandwich and convey the paper P upward, and a second orientation changing member that changes the conveyance direction of the recording paper P conveyed by the conveyance roller pair 48 to the front side of the printer. 49, a pressure-conveying conveyance roller pair 50 that is disposed at the downstream end of the U-turn portion 45 and sandwiches the recording paper P and discharges it from the U-turn portion 45, and is disposed in the vicinity of the conveyance roller pair 50. And that the recording paper P is in this position The third sensor 51 for output (consisting of a light projecting unit and the light receiving portion) are provided. A pair of guide plates 52 for guiding the leading end of the recording paper P fed from the lower conveyance roller pair 48 to the upper conveyance roller pair 48 is provided between the two conveyance roller pairs 48. It is arrange | positioned so that it may be pinched | interposed.

  Between the two pairs of conveying rollers 46 in the upstream portion of the U-turn portion 45, a drying air W for drying the ink adhering to the upper surface of the recording paper P in the printing portion 21 is supplied to the recording paper P. A drying device 53 for spraying on the upper side surface is provided. The drying device 53 has a suction fan 54 for taking air into the drying device 53, a heater 55 for heating the air taken in by the suction fan 54, and an opening at the lower end of the drying device 53. An exhaust nozzle unit 56 that blows air heated by the heater 55 on the upper surface of the recording paper P as dry air W, and a safety thermo 57 that detects the temperature in the drying device 53 and stops the heater 55 in an emergency manner. Yes.

  Of all the conveying roller pairs 46, 48, 50 of the U-turn portion 45, rollers (two pairs of conveying rollers 46 in the upstream portion) that contact the surface of the recording paper P opposite to the printing surface by the printing unit 21. Are the lower rollers, the downstream two pairs of conveying rollers 48 are the rear rollers of the printer, and the upper conveying rollers 50 are the driving rollers 46a, 48a, 50a, respectively. The rollers that come into contact with the printing surface (the upper roller in the conveyance roller pair 46, the front roller in the conveyance roller pair 48, and the lower roller in the conveyance roller pair 50) are respectively The driven rollers 46b, 48b, and 50b are used. These driven rollers 46b, 48b, 50b are made of a softer material than the drive rollers 46a, 48a, 50a. For example, the drive rollers 46a, 48a, and 50a are made of polypropylene, and the driven rollers 46b, 48b, and 50b are made of foamed urethane. In this way, by allowing the driven rollers 46b, 48b, and 50b that are in contact with the printing surface to be soft, it is possible to increase the permissible speed of the conveyance speed of the recording paper P. Further, by making the driving rollers 46a, 48a, 50a in contact with the surface opposite to the printing surface hard, it is possible to secure the conveyance accuracy of the recording paper P and to prevent the occurrence of meandering.

  All the driving rollers 46a, 48a, 50a are driven by the same motor (not shown). The rotational speeds of the drive rollers 46a, 48a, 50a, that is, the transport speed of the recording paper P by the transport roller pairs 46, 48, 50 are configured to be variable. That is, the degree of drying of the ink by the drying device 53 changes according to the environmental conditions (temperature, humidity, etc.) in which the ink jet printer A is installed, so the transport speed is changed accordingly. Further, when the duplex printing unit 7 is attached to the printer main body 1, the ink may be dried while the recording paper P is conveyed by the duplex printing unit 7. Set to a relatively fast speed so that the ink does not dry completely. On the other hand, when the duplex printing unit 7 is not attached to the printer main body 1 (see FIG. 10), the recording paper P discharged from the U-turn unit 45 by the pair of conveying rollers 50 is directly outside the housing 2. The ink is discharged and placed on the upper surface of the housing 2, and for this reason, a slow speed is set so that the ink is almost completely dried by the drying device 53.

  The third sensor 51 detects the trailing edge of the recording paper P and detects the discharge of the recording paper P from the U-turn portion 45. When the duplex printing unit 7 is not attached to the printer main body 1, the discharge of the recording paper P to the outside of the housing 2 is detected. On the other hand, when the duplex printing unit 7 is attached to the printer main body 1, when the recording paper P is transported by an amount in which the trailing edge deviates from the transport roller pair 50 from detection of the trailing edge of the recording paper P. In addition, the conveyance speed of the recording paper P in the duplex printing unit 7 is changed (up).

  The duplex printing unit 7 has a two-part structure of a first unit 8 that covers the upper surface of the housing 2 and a second unit 9 that is located above the cassette 5. Only the first unit 8 can be detached from the housing 2 in a state where the duplex printing unit 7 is attached to the printer main body 1. With the first unit 8 removed, maintenance work is performed on the printing unit 21 (especially the print head H, etc.) through a maintenance opening (normally closed with a lid) provided on the top surface of the housing 2. be able to. Therefore, even after the duplex printing unit 7 is attached to the printer main body 1, the maintenance work of the printing unit 21 can be easily performed.

  In the first unit 8 of the double-sided printing unit 7, the recording paper P sent out from the U-turn unit 45 passes the printing unit 21 to the cassette 5 side (the printer front side with respect to the printing unit 21). A reverse transport unit 61 is provided for transporting to the front. The reverse conveyance unit 61 includes three pairs of pressure-conveying conveyance rollers 62 that sandwich the recording paper P and convey the recording paper P to the front side of the printer, and a downstream end of the reverse conveyance unit 61 (the front end of the first unit 8 on the printer). And a fourth sensor 63 (consisting of a light projecting part and a light receiving part) for detecting that the recording paper P is in the position.

  The transport path in the reverse transport unit 61 is a straight path slightly inclined downward toward the front side of the printer. The reason for this inclination is as follows. That is, the height position of the conveying roller pair 50 of the U-turn portion 45 is sufficient on the upper surface of the housing 2 on which the recording paper P is placed when the duplex printing unit 7 is not attached to the printer main body portion 1. It is necessary to be at a height position where the number of recording sheets P can be placed. On the other hand, in a switchback unit 66 (described later) in the second unit 9, the number of supply roller pairs 69 (described later) that supplies the switched back recording paper P to the upstream end of the print transport unit 22 is set to the minimum of the recording paper P. It is desirable to reduce as much as possible in consideration of the relationship with the length, and for this purpose, the switchback unit 66 needs to be at a height position close to the print conveyance unit 22. For this reason, the conveyance path in the reverse conveyance unit 61 that connects the U-turn unit 45 and the switchback unit 66 is inclined as described above.

  In the entire transport roller pair 62 of the reverse transport unit 61, a roller (upper roller) that contacts the surface of the recording paper P opposite to the print surface of the print unit 21 is a drive roller 62a, and the print surface The roller (lower roller) in contact with is a driven roller 62b. Similar to the conveying roller pair 46, 48, 50 of the U-turn portion 45, the driven roller 62b is made of a softer material than the driving roller 62a.

  All the driving rollers 62a are driven by the same motor (not shown). The rotational speed of the drive roller 62a, that is, the transport speed of the recording paper P by the transport roller pair 62, is the same as that of the drive rollers 46a, 48a, 50a of the transport roller pairs 46, 48, 50 of the U-turn section 45. It is configured to be variable. As described above, from the detection of the trailing edge of the recording sheet P by the third sensor 51, the conveying speed is increased when the recording sheet P is conveyed by an amount by which the trailing edge deviates from the conveying roller pair 50. That is, since the conveyance path is curved in the U-turn portion 45, it is necessary to set a speed at which the printing surface can be stably conveyed without damaging the printing surface, and the trailing edge of the recording paper P is upstream of the conveyance roller pair 50 In this state, the conveyance speed of the recording paper P by the conveyance roller pair 62 needs to be the same as the conveyance speed in the U-turn unit 45, but if the trailing edge of the recording paper P is separated from the conveyance roller pair 50, Since the recording paper P is transported along the straight transport path, the allowable speed is increased and the transport speed is increased. However, the transport speed is adjusted according to the status (the number of existing sheets and the existing position) of the recording paper P existing on the downstream side.

  In the second unit 9, the recording paper P transported from the reverse transport unit 61 is switched back and supplied from the rear end side of the recording paper P to the upstream end of the printing transport unit 22. A switchback portion 66 is provided. The switchback portion 66 is provided with a pressure-sensitive switchback roller pair 67 composed of a lower driving roller 67 a and an upper driven roller 67 b, and a conveyance path on the upstream side of the switchback roller pair 67. The pair of first guide members 68 that guide the recording paper P conveyed from the reverse conveying unit 61 to the switchback roller pair 67 and the switched back recording paper P are supplied to the upstream end of the printing conveying unit 22. A pair of pressure-feeding supply rollers 69, a pair of switchback rollers 67, and a pair of supply rollers 69, and a pair of second guides that guide the switched back recording paper P to the supply roller pair 69. A guide member 70 is provided.

  The drive roller 67a of the switchback roller pair 67 is driven forward by a motor (not shown) sandwiching the recording paper P and transported to the front side of the printer, and reversely rotated by sandwiching the recording paper P and transported to the rear side of the printer. Is configured to be possible.

  The switchback roller pair 67 and the first guide member 68 can be integrally rotated around the rotation axis of the drive roller 67a of the switchback roller pair 67 by a motor (not shown). A driven roller 67b of the roller pair 67 is positioned at a first position (see FIG. 6) substantially directly above the driving roller 67a, and a second position is positioned at the rear side of the printer with respect to the driving roller 67a (see FIG. 6). 7). Further, when the driven roller 67b is in the first position, the first guide member 68 is positioned on the extension of the transport path in the reverse transport unit 61 (see FIG. 6), and the driven roller 67b is in the second position. Sometimes, it is located on the extension of the second guide member 70 (see FIG. 7).

  Here, a method of switching back the recording paper P conveyed from the reverse conveyance unit 61 will be described. When the switchback roller pair 67 receives the recording paper P conveyed from the reverse conveying unit 61, the driving roller 67a is rotating forward and the driven roller 67b is in the first position. Then, after the fourth sensor 63 detects the trailing edge of the recording paper P, the recording paper P is conveyed to the front side of the printer by the switchback roller pair 67 by such an amount that the trailing edge is positioned on the first guide member 68. Then (see FIG. 6), the forward rotation of the drive roller 67a is stopped. At this time, at least the front end portion of the recording paper P is positioned on a loading tray 74 described later.

  Subsequently, the switchback roller pair 67 and the first guide member 68 are rotated clockwise in FIG. 6 to switch the driven roller 67b from the first position to the second position. As a result, the leading end side (front side of the printer) of the recording paper P is lifted and curved in a state of being in contact with the two auxiliary rollers 72 disposed on the upper side of the switchback roller pair 67 and on the front side of the printer ( (See FIG. 7).

  Thereafter, the drive roller 67a is rotated in the reverse direction, and the recording paper P is conveyed from the rear end side toward the supply roller pair 69 side. At this time, the auxiliary roller 72 rotates as the recording paper P is transported, so that the rear end side portion of the recording paper P to be switched back (corresponding to the front end side portion when the drive roller 67a is rotated forward) is smooth. While moving, the inner wall surface of the second unit 9 is not rubbed and scratched. The recording paper P to be switched back by the switchback roller pair 67 reaches the supply roller pair 69 through the first guide member 68 and the second guide member 70 (see FIG. 8).

  The supply roller pair 69 includes a driving roller 69a driven by a motor (not shown) and a driven roller 69b pressed against the driving roller 69a. The pressure-bonded state of the driven roller 69b to the drive roller 69a can be released as will be described later (the same applies to the driven roller 67b of the switchback roller pair 67).

  Below the supply roller pair 69, a pair of third guide members 73 provided on the upper part of the front side of the printer in the casing 2 of the printer main body 1 are disposed so as to sandwich the conveyance path. The recording paper P is supplied to the upstream end portion of the print transport unit 22 through the third guide member 73. Thus, the upper side surface of the recording paper P supplied to the print transport unit 22 via the duplex printing unit 7 is the surface (hereinafter referred to as the front side surface) that is first printed on the recording paper P by the printing unit 21. ) Is a surface on the opposite side (hereinafter referred to as a back side surface), which has not been printed yet. And it prints on both surfaces of the said recording paper P by printing on a back side surface similarly to the time of the first printing.

  The switchback roller pair 67 also serves to discharge the recording paper P conveyed from the reverse conveyance unit 61 to the outside of the second unit 9 without switching back. That is, when discharging the recording paper P to the outside of the second unit 9, the switchback roller pair 67 continues to rotate without stopping the forward rotation of the driving roller 67a. On the front side of the printer on the outer wall of the second unit 9, there is provided a loading tray 74 for receiving and loading the recording paper P sent out by the switchback roller pair 67. The recording paper P printed on both sides as described above and the recording paper P that can be printed only on the front side are discharged to the outside of the second unit 9 by the switchback roller pair 67 and placed on the placement tray 74. Will be.

  A cover member 75 for preventing dust and the like from adhering to the recording paper P placed on the placement tray 74 is placed on the upper side of the placement tray 74 on the front side of the printer on the outer wall of the second unit 9. A cantilever is supported so as to cover the upper side of the placing tray 74. The cover member 75 is supported at the base end portion (the rear end portion of the printer) so as to be rotatable around a shaft 75a extending in the left-right direction of the printer, and the cover member 75 is rotated around the shaft 75a. It is also possible to make it stand up so as to extend upward from the end.

  In the vicinity of the switchback roller pair 67 on the upper surface of the outer wall of the second unit 9, a manual insertion opening 77 through which the recording paper P can be manually inserted is formed. In the manual insertion opening 77, a pair of manual insertion guide members 78 are disposed so as to sandwich the manually inserted recording paper P in the thickness direction, and the manual insertion guide member 78 allows manual recording. The leading edge of the paper P is guided to the switchback roller pair 67 side. Further, the manual insertion opening 77 is covered with a lid member 79 (see FIG. 1), and when the user manually inserts the recording paper P, the user opens the lid member 79 and a mode (not shown). Operate the switch to switch to manual feed mode. As a result, as shown in FIG. 9, the driven roller 67b of the switchback roller pair 67 is switched to the second position, and the drive roller 67a rotates in the reverse direction. Then, the user inserts the recording paper P from the manual insertion opening 77. At this time, if the cover member 75 is in an upright state, the cover member 75 serves as a tray for supporting the recording paper P, and insertion of the recording paper P becomes easy. When the recording paper P is inserted through the manual insertion opening 77 in this way, the recording paper P is conveyed toward the supply roller pair 69 by the switchback roller pair 67, and is the same as the recording paper P which is switched back and conveyed. In addition, the supply roller pair 69 supplies the print conveyance unit 22 (printing unit 21).

  A pair of left and right width regulating members (not shown) are provided on the left and right sides of the second guide member 70 in the switchback portion 66 so as to abut on both sides in the width direction of the recording paper P supplied to the print transport unit 22. ing. The left and right width restricting members are bent so as to form rectangular grooves that open on the opposing surfaces, and the bottom surfaces of these grooves are in contact with both side edges of the recording paper P in the width direction. Each width regulating member can adjust the position in the left-right direction of the printer.

  The U-turn section 45, the reverse transport section 61, and the switchback section 66 connect the downstream end and the upstream end of the print transport section 22 and surround the print head H together with the print transport section 22. The recording paper P printed on the front side surface, which is formed from the downstream end of the print transport unit 22 and forms a circular transport path, is reversed and fed to the upstream end of the print transport unit 22. The recording paper resupply unit 88 is configured. By this recording paper refeeding unit 88, the recording paper P printed on the front side can be reversed and fed back to the printing unit 21, and printing can also be performed by printing on the back side of the recording paper P. Printing can be performed on both sides of the paper P.

  The recording paper P printed on the back side is switched by the U-turn unit 45 and the reverse transport unit 61 in the same way as when transported after printing on the front side (during the first transport of the recording paper P). It is conveyed to the back part 66. At this time, the switchback roller pair 67 of the switchback unit 66 continues to rotate normally, and the recording paper P is discharged onto the loading tray 74. When the recording paper P printed on the back side is transported by the U-turn unit 45 and the reverse transporting unit 61, the drive rollers 46a, 48a, 50a, 62a of the transport roller pairs 46, 48, 50, 62 are the recording paper. At this point of time, the ink attached to the front side is completely dry, so there is a problem even if the recording paper P is transported at the same speed as the first transport. There is no. However, in order to further improve the print quality, it is possible to make the conveyance speed at the second conveyance slower than at the first conveyance.

  The recording paper resupply unit 88 is capable of holding at least one recording paper P printed before the recording paper P while the printing unit 21 is printing on one recording paper P. It is set to length. As a result, the period from printing on the front side of one recording sheet P to printing on the back side can be used for printing at least one subsequent recording sheet P.

  For example, when performing double-sided printing on the smallest recording paper P among the plurality of sizes, the first to fourth recording paper P is continuously supplied from the cassette 5 to the printing unit 21. The printing unit 21 continuously prints on the front side of the recording paper P. When printing is performed on the fourth recording sheet P, the three recording sheets P that have been printed first are located in any part of the recording sheet resupply unit 88 (usually, The first recording paper P is located in the switchback unit 66, the second recording paper P is located in the reverse conveyance unit 61, and the third recording paper P is located in the U-turn unit 45). When the printing on the fourth recording paper P is completed, the first recording paper P printed on the front side is supplied to the printing unit 21 and the back side of the first recording paper P Printing is performed on the front side, and then printing is continuously performed on the back side of the second to fourth recording sheets P. When printing is performed on the back side surface of the fourth recording sheet P, the first recording sheet P is discharged onto the loading tray 74 by the switchback roller pair 67, and the second and third sheets. The recording paper P is located in the reverse conveyance unit 61 and the U-turn unit 45, respectively.

  When printing on the back side surface of the fourth recording sheet P is completed, the fifth to eighth recording sheets P are continuously supplied from the cassette 5 to the printing unit 21, and are supplied to the printing unit 21. Then, printing is continuously performed on the front side of the recording paper P. In this way, printing is sequentially performed on the front side surface and the back side surface of the recording paper P as a set of four recording papers P. In addition, it is also possible to interpose a set for performing single-sided printing between two sets for performing double-sided printing.

  Therefore, when performing duplex printing on only one recording sheet P, the recording sheet P printed on the front side passes through the long conveyance path of the recording sheet refeeding unit 88 and then the back side of the recording sheet P. However, when printing on both sides of a predetermined number or more of recording sheets for business use or the like, at least one recording sheet P is loaded by the recording sheet refeeding unit 88. Printing can be performed on other recording paper P during conveyance, and the print processing capability can be improved. In addition, the ink attached to the front side of the recording paper P in the printing unit 21 can be sufficiently dried before printing on the back side, and printing is performed by printing on the back side in this dry state. Both sides of the paper P are not wetted with ink at the same time, and it is possible to reliably prevent the occurrence of show-through due to ink penetration. Further, curling and undulation phenomena are less likely to occur on the recording paper P. Therefore, it is possible to prevent the print quality of the recording paper P from being deteriorated.

  As shown in FIG. 11, the print transport mechanism that transports the recording paper P during printing includes a first print transport unit 101 that transports the recording paper P onto the support surface 23 a of the platen 23, and a support surface 23 a of the platen 23. A second print transport unit 102 that unloads the recording paper P from above and a stepping mechanism are provided. The first print transport unit 101 and the second print transport unit 102 are controlled by a transport control unit 202 described later.

  The first print transport unit 101 includes the first transport roller pair 24 described above, the first motor 104 that drives the first transport roller pair 24, and the first rotary encoder 105 for the first motor 104. have. Specifically, the first transport roller pair 24 includes a first driving roller 24a positioned on the lower side and a first driven roller 24b positioned on the upper side, and the first driving roller 24a includes the sprocket 106 and the belt. The first motor 104 is connected to the first motor 104 via a transmission mechanism 107. The first motor 104 is provided with a first rotary encoder 105 that can measure the rotation angle and rotation speed with high accuracy.

  Similarly, the second print transport unit 102 also includes the second transport roller pair 25 described above, the second motor 108 that drives the second transport roller pair 25, and the second rotary encoder for the second motor 108. 110, and the second conveying roller pair 25 includes a second driving roller 25a positioned on the lower side and a second driven roller 25b positioned on the upper side. The second driving roller 25a is connected to the sprocket 106. It is connected to the second motor 108 via a transmission mechanism constituted by a belt 107. A second rotary encoder 110 is also attached to the second motor 108. The first motor 104 and the second motor 108 are constituted by high-precision servo motors, and operate in response to a command from a conveyance control unit 202 described later.

-Traversing mechanism-
As shown in FIG. 11 and FIG. 13, the step changing mechanism is composed of a pair of arms 112, 112, a cam member 114, and the like.

  Each arm 112 includes an arm base portion 112a whose base end portion is rotatably supported around shafts 115 and 116 extending in the left-right direction of the printer, and a roller receiver that extends to the arm base portion 112a and extends substantially orthogonally to the base end portion. Part 112b and a cam engaging part 112c extending in a facing manner to the roller receiving part 112b connected to the tip of the arm base part 112a. Since the cam engaging portion 112c is formed sufficiently longer than the roller receiving portion 112b, the arm 112 is L-shaped in appearance. Each arm 112 is disposed so that the tip end sides of the respective cam engagement portions 112c face each other, and the tip end sides of these cam engagement portions 112c are respectively urged by springs (not shown) in the downward direction. Yes. The first driven roller 24b and the second driven roller 25b are rotatably supported at the distal end side of each roller receiving portion 112b, and the cam member 114 and the second driven roller 25b are rotatably supported at the distal end side of each cam engaging portion 112c. Engaging cam engagement rollers 117 and 117 are rotatably supported.

  The cam member 114 is composed of a relatively large-diameter roller member having a notch 114a obtained by cutting a part of the periphery of the cam member 114, and is close to the two cam engagement rollers 117 and 117 at a lower position therebetween. It is arranged. The cam member 114 is rotatably supported by a shaft extending in the left-right direction of the printer, and is rotationally driven by a motor 118 (hereinafter referred to as a switching motor 118) via a transmission mechanism. The operation of the stepping motor 118 is controlled by a conveyance control unit 202 described later.

  In a state where the notch 114a of the cam member 114 is positioned above and does not contact the cam engagement roller 117 of each arm 112, the first driven roller 24b supported by the roller receiving portion 112b by the biasing force of the spring. And the second driven roller 25b are respectively pressed against the first drive roller 24a and the second drive roller 25a, and as shown in FIG. 13, the cam engagement portions 112c of the arms 112 extend substantially horizontally so as to extend on the same straight line. It is located (crimped state).

  When the cam member 114 is rotationally displaced and its circumferential portion abuts against the cam engagement roller 117 of one of the arms 112, the direction in which the tip end side of the cam engagement portion 112c faces upward against the spring. Then, the arm 112 rotates. By doing so, both or one of the first driven roller 24b and the second driven roller 25b are separated from the respective drive rollers 24a and 25a, and the pressure-bonded state is released (released state).

  That is, the recording paper P is switched by switching between the pressure-bonded state and the released state of each of the conveying roller pairs 24 and 25, and the first sensor 27 and the second sensor 28 described above cooperate. Therefore, the conveyance control unit 202 executes the control (step change control).

  The first sensor 27 detects that the leading edge of the recording paper P has entered the casing 2 of the printer main body 1 from the cassette 5 or the duplex printing unit 7. For example, by this detection, the conveyance control unit 202 is detected. Thus, the first driving roller 24a is driven. The second sensor 28 detects the leading edge of the recording paper P sent to the platen 23 side by the first conveyance roller pair 24. For example, the second sensor 28 detects the leading edge of the recording paper P by the second sensor 28. The printing timing is calculated, and printing on the recording paper P is started at the printing timing. Further, the detection of the leading edge of the recording paper P by the second sensor 28 is also a base point of the step change control.

-Composition of reception block-
The reception block 200 (see FIG. 15) includes a reception device (not shown) for reading image data recorded on a recording medium such as a DVD, and an input device including a touch panel type liquid crystal monitor. Although not shown, the accepting device and the input device are connected to the print control unit 204 via the communication interface 206.

  When the inkjet printer A is turned on, the input device displays a mode selection screen 130 (see FIG. 16A) on the liquid crystal monitor. The mode selection screen 130 is a screen for the user to set the print mode. The screen 130 includes a “normal print mode” button 131 and a “test print mode” button 132 that can be selected by the user with a finger. It is displayed.

  When the “normal printing mode” button 131 is selected, the input device outputs the selection signal to the print control unit 204 (see FIG. 15), and displays the monitor display screen as an order information input screen (illustrated). Switch to (omitted). Here, the order information includes print channel information for specifying the size of the recording paper P to be printed, and print form information for specifying the number of printed sheets. Further, when the “test print mode” button 132 is selected, the input device outputs the selection signal to the print control unit 204, and displays the display screen of the liquid crystal monitor from the mode selection screen 130 to the correction value input screen. Switch to 133 (see FIG. 16B).

  The correction value input screen 133 is a screen for the user to input the reference correction pulse numbers of the motors 104 and 108. Here, the reference correction pulse number is the predetermined time point of the command pulse number of each of the motors 104 and 108 necessary for transporting the reference recording paper P by the set feed amount D with the front side as the printing surface at the present time. The amount of change from the above (shift amount) is calculated by the user based on the result of test printing described later. The correction value input screen 133 displays numerical value input buttons 134 arranged in a calculator format, and the user can input a desired reference correction pulse number via the numerical value input button 134. The input device outputs information on the number of input reference correction pulses to the print control unit 204.

-Control system configuration-
As shown in FIG. 15, the inkjet printer A has a microprocessor 201 (hereinafter referred to as a CPU), a conveyance control unit 202 connected to the CPU 201 via a data bus, a head control unit 203, and a print system. A control unit 204, a semiconductor memory RAM / ROM 205, and a communication interface 206 are provided.

  The print control unit 204 receives image data, order information, and mode information from the receiving block 200 via the communication interface 206. When receiving a selection signal indicating that the normal printing mode is selected, the print control unit 204 executes normal printing control for printing the image data received from the receiving block 200 on the recording paper P. In the present embodiment, when executing the normal printing control, the print control unit 204 records the recording paper P based on correction table data M (described later) stored in the ROM 205 in advance (see FIG. 17A). The feed amount of the recording paper P is maintained at the set feed amount D by correcting the number of command pulses of the motors 104 and 108 according to the kind of the motor.

  When the print control unit 204 receives a selection signal indicating that the test print mode has been selected, the print control unit 204 executes test print control for printing a plurality of straight lines arranged in the recording sheet conveyance direction on the left and right sides of the recording sheet.

  The transport control unit 202 receives a command from the print control unit 204 and controls the operation of the print transport mechanism. The conveyance control unit 202 executes the switching control by outputting a necessary control signal to each of the conveyance units 101 and 102 when the print control unit 204 executes print control.

  The head control unit 203 controls the print head H by receiving a command from the print control unit 204 and reciprocating the print head H in the main scanning direction and supplying a voltage having a predetermined waveform to each piezoelectric element. It is.

-Step-change control in the transport controller-
FIG. 14 schematically shows the operation of each pair of conveyance rollers 24 and 25 when the conveyance control unit 202 executes the step-change control. First, as shown in FIG. 2A, the leading edge of the recording paper P enters the casing 2 of the printer main body 1 and the first driving roller 24a is driven. When P is carried onto the platen 23, the tip of the second sensor 28 is detected. Then, the conveyance control unit 202 calculates the timing at which the leading end portion of the recording paper P reaches the second conveyance roller pair 25. Then, at the timing as shown in FIG. 5B, the conveyance control unit 202 controls the cam member 114, that is, rotates and displaces the cam member 114 to a predetermined angle. As a result, the first driven roller 24b rotates together with the roller receiving portion 112b around the shaft 115 in the counterclockwise direction in the figure, and the pressure-bonded state of the first conveying roller pair 14 is released. Also, substantially simultaneously with the release of the pressure bonding, the second driven roller 25b rotates together with the roller receiving portion 112b around the shaft 116 in the counterclockwise direction in the figure, so that the second conveying roller pair 25 is switched from the non-pressure bonded state to the pressure bonded state. Change. After that, the recording paper P is unloaded from the platen 23 by the second conveying roller pair 25 as shown in FIG.

  In this way, the switching control for alternately switching the first conveying roller pair 24 and the second conveying roller pair 25 is performed because one sheet of recording paper P is simultaneously pressure-bonded to both the conveying roller pairs 24 and 25 and conveyed. This is because the recording paper P may be excessively pulled or bent due to a shift in the conveying force between the pair of conveying rollers 24 and 25, resulting in a problem in printing.

  Therefore, the recording paper P is reliably prevented from being simultaneously conveyed by the first conveying roller pair 24 and the second conveying roller pair 25 by the switching mechanism and the switching control in this manner, thereby stabilizing a high-quality image. It has come to be obtained.

-About correction table data-
The correction table data M indicates the number of command pulses of the motors 104 and 108 necessary for transporting the recording paper P by the set feed amount D at a predetermined time (for example, when the printer is shipped from the factory), at the predetermined time. The recording paper P in the form of a difference amount (hereinafter referred to as individual correction pulse number) with respect to the command pulse number of each of the motors 104 and 108 necessary for transporting the paper P by the set feed amount D with the front side as the printing surface. This is set for each of the front and back sides for each type.

  In the present embodiment, as shown in FIG. 17A, each of the front side surface and the back side surface is different from the three types of recording paper P, that is, the reference recording paper P, the first recording paper P, and the second recording paper P. The number of individual correction pulses is set for. FIG. 17B is a table showing the material and size of each type of recording paper P. In this embodiment, the reference recording paper P is A4 size plain paper, and the first recording paper P Is a B5 size plain paper, and the second recording paper P is an A4 size coated paper.

  The correction table data M is created by performing setting printing at the time of shipment from the manufacturer of the printer A.

  In this setting printing, the number of theoretical command pulses of the motors 104 and 108 necessary for transporting the recording paper P by the set feed amount D is obtained in advance, and the motors 104 and 108 are controlled by the number of theoretical command pulses. The following printing process is executed while intermittently driving. As shown in FIG. 19A, first, ink is ejected from the downstream head unit 32 to an area on the left side of the printer (hereinafter simply referred to as the left side) with respect to the center position in the width direction on the front side surface of the recording paper P. A plurality of test lines L extending in the main scanning direction are printed at equal intervals (see FIG. 19A). Then, after the recording paper P is intermittently conveyed by a predetermined number N, this time, the ink is discharged from the upstream head unit 32 to the area on the right side of the printer (hereinafter simply referred to as the right side) from the central position in the width direction of the recording paper P. As a result, a plurality of test lines L are printed in the same manner as in the left area (see FIG. 19B).

  The operator measures (acquires) a deviation amount S in the recording sheet conveyance direction of the left and right test lines L printed on the recording sheet P by the setting printing by using a microscope. The operator calculates a value (= S / N) obtained by dividing the measured deviation amount S by the predetermined number N as a feed amount error of the recording paper P, and each motor necessary for eliminating this feed amount error. The number of correction pulses 104 and 108 is calculated. The operator executes this series of operations (setting printing and calculation of feed error) for each type of recording paper P, and calculates the number of correction pulses for each of the front side printing and the back side printing. The operator calculates the number of correction pulses calculated in this manner as the number of individual correction pulses in the form of a difference amount (for example, a ratio) with respect to the number of correction pulses at the time of surface printing of the reference recording paper P. Correction table data M is created based on the number of individual correction pulses. Then, the operator stores the created correction table data M in the ROM 205 using a personal computer or the like (data storage step). In the correction table data M shown as an example in FIG. 17A, for example, the number of command pulses of the first motor 104 necessary for transporting the recording paper P by the set feed amount D during surface printing of the first recording paper P. It can be seen that the (individual correction pulse number) is increased by 6 pulses compared to the surface printing of the reference recording paper P.

  In addition, the user stores the sum of the correction pulse number and the theoretical command pulse number in the front surface printing of the reference recording paper P calculated based on the setting printing in the ROM 205 as the reference pulse number.

-Print control in the print controller-
Next, print control in the print control unit 204 will be described with reference to the flowchart of FIG.

  In the first step S1, image data and order information from the receiving block 200, and recording sheet detection information from each sensor are read.

  In step S2, it is determined whether or not the normal mode is selected. When this determination is YES, the process proceeds to step S3, and when it is NO, the process proceeds to step S13.

  In step S3, it is determined whether or not there is a print request from the order information read in step S1. If this determination is NO, the process returns. If YES, the process proceeds to step S4.

  In step S4, the reference pulse number stored in advance in the ROM 205 is read.

  In step S5, the reference correction pulse number input by the user is read from the correction value input screen 133 of the liquid crystal monitor.

  In step S6, the type of the recording paper P input by the user is read from the receiving block 200.

  In step S7, it is determined whether the printing surface of the recording paper P is the front side or the back side.

  In step S8, based on the correction table data M, the type of recording paper and the number of individual correction pulses corresponding to the front / back are acquired.

  In step S9, the number of pulses obtained by adding the number of reference pulses, the number of reference correction pulses, and the number of individual correction pulses is calculated as the command pulse number of each motor 104,. Then, information on the calculated command pulse number is output to the transport control unit 202.

  In step S10, after the conveyance control unit 202 drives the motors 104 and 108 to rotate by the command pulse and stops the rotation, the head control unit 203 causes the print head H to perform one scan in the main scanning direction. A control signal is output accordingly.

  In step S11, it is determined whether or not printing on the front side surface of the recording paper P has been completed. When this determination is NO, the process returns to step S7, while when it is YES, the process proceeds to step S12.

  In step S12, it is determined whether or not printing on the back side surface of the recording paper P has been completed. When this determination is NO, the process returns to step S7, while when it is YES, the process returns.

  In step S <b> 13, necessary control signals are output to the head control unit 203 and the conveyance control unit 202 in order to execute test print control (the same print processing as the initial setting print).

  In step S14, a command is issued to the input device to switch the display screen of the liquid crystal monitor from the mode selection screen 130 to the correction value input screen 133.

  In step S15, it is determined whether or not a reference correction pulse number has been input. If this determination is NO, the process returns to step S14, whereas if YES, the process proceeds to step S16.

  In step S16, the reference correction pulse number input in step S15 is stored in an auxiliary storage device (not shown), and then the process returns.

  In the printer A configured as described above, when the user desires test printing on the recording paper P, the cassette 5 in which the reference recording paper P is accommodated in advance is attached to the printer main body 1, and then the printer A The test print mode may be selected via the mode selection screen 130.

  As a result, when the test print control is executed by the print control unit 204 (by executing the process of step S13), the recording paper P has left and right areas sandwiching the central position in the width direction. A plurality of test lines L (see FIG. 19) arranged in the transport direction are printed.

  The user measures a deviation amount S of the left and right test lines L in the recording paper conveyance direction with a microscope, and a value obtained by dividing the deviation amount S by the predetermined number N is a feed amount error of the reference recording paper P. Judgment can be made. Then, the user may calculate the number of correction pulses of the motors 104 and 108 necessary to eliminate this error amount, and input the calculated correction pulse number from the correction value input screen 133 as the reference correction pulse number. . As a result, when normal print control on the recording paper P is executed by the print control unit 204, a value obtained by adding the reference correction pulse number to the reference pulse number is set as the command pulse number of each motor 104, 108. (The process of step S9 is executed). Therefore, the frictional resistance between the recording paper P and each roller at the present time is caused by the change over time such as the wear of each roller constituting each pair of transport rollers 24 and 25 and the change in the amount of paper dust attached to each roller. Even if it changes from the time, by correcting the number of command pulses of the motors 104 and 108 by the number of reference correction pulses, it is possible to reliably suppress the feeding amount error of the recording paper P accompanying the change in the frictional resistance. .

  Further, in the present embodiment, when the print control unit 204 executes normal printing control on the recording paper P, the type of the recording paper P and the printing surface of the recording paper P are the front side and the back side. In accordance with either, the corresponding individual correction pulse number is read from the correction table data M, and a value obtained by adding the individual correction pulse number to the reference pulse number is set as the command pulse number of each of the motors 104 and 108 ( Step S9 is executed). Accordingly, the type of the recording paper P changes or the printing surface of the recording paper P changes from the front side surface to the back side surface, so that the frictional resistance (conveyance resistance) between the recording paper P and each of the conveyance roller pairs 24 and 25 is increased. Even if it changes, the feed amount error of the recording paper P due to the change in the frictional resistance can be reliably suppressed by correcting the command pulse number of each motor 104, 108 by the number of individual correction pulses.

  This change in frictional resistance may occur depending on the material of the recording paper P, the size of the recording paper P, etc. (the type of the recording paper P), and the recording paper transport path differs between the back side printing and the front side printing. It may be caused by a change in bending characteristics due to the above. For this reason, it is difficult to quantitatively estimate this frictional resistance by calculation. On the other hand, if the correction table data M is created in advance by test printing as in the present embodiment, and the number of command pulses of the motors 104 and 108 is changed based on the correction table data M, recording is performed. Even if the frictional resistance cannot be theoretically calculated according to the type of the paper P or the front and back of the printing surface, the feeding amount error of the recording paper P can be reliably suppressed.

(Other embodiments)
The configuration of the present invention is not limited to the above embodiment, but includes various other configurations. That is, in the embodiment, the operator measures the shift amount S of the test line L of the recording paper P with a microscope and creates the correction table data M based on the measured value. For example, the CPU 201 may automatically perform a series of processes from the measurement of the deviation amount to the creation of the correction table data M. Specifically, for example, a plurality of test lines L printed on the recording paper P are read by the image sensor, and the correction table data M is created by calculating the deviation amount S based on the read image by the CPU 201. You just have to do it.

  Moreover, in the said embodiment, the example which applied the conveyance adjustment method based on this invention with respect to the inkjet printer A was shown, It does not restrict to this, For example, you may make it apply to a laser printer.

  In the embodiment, the recording paper P is intermittently conveyed during printing. However, the recording paper P may be continuously conveyed during printing, such as a laser printer. The feed amount in the case of continuous conveyance means, for example, the conveyance amount per unit time of the recording paper P.

  The present invention includes a transport mechanism that transports recording paper with a preset set feed amount, and a printing unit that performs printing on the recording paper transported by the transport mechanism, and prints on a plurality of types of recording paper. The present invention is useful for a printer conveyance adjustment method that can be configured, and is particularly useful for a printer conveyance adjustment method in which recording paper is intermittently conveyed by a set feed amount by a conveyance mechanism.

A Inkjet printer M Correction table data P Recording paper 21 Printing section 24 First transport roller pair (transport mechanism)
25 Second transport roller pair (transport mechanism)

Claims (3)

It has a transport mechanism that transports recording paper at a preset feed amount and a printing unit that prints on the recording paper transported by the transport mechanism, and is configured to print on multiple types of recording paper. A method for adjusting the conveyance of a printer,
A type detecting step of detecting a type of recording paper to be printed by the printing unit;
Necessary driving amount of the transport mechanism necessary for transporting a predetermined type of reference recording paper at a predetermined time point by the set feed amount, and transport necessary for transporting recording paper other than the reference recording paper by the set feed amount A data storage step of acquiring a value indicating an amount of deviation from the required drive amount of the mechanism, and storing the acquired value in advance as correction data for each type of the recording paper;
A measuring step of measuring a value related to a deviation amount from the predetermined time point of a required drive amount of a transport mechanism necessary for transporting the reference recording paper by the set feed amount at the present time;
Based on the correction data stored in the data storage step and the value measured in the measurement step, the feeding amount of the recording paper is set according to the type of recording paper detected in the type detection step. A control step of controlling the drive amount of the transport mechanism so as to be a feed amount;
A method for adjusting the conveyance of a printer, comprising: The conveyance adjustment method of the printer according to claim 1.
The printing unit is configured to print on the back side after printing on the front side of the recording paper,
A front / back determination step of determining whether the printing surface of the recording paper to be printed by the printing unit is the front side or the back side;
In the data storage step, when the reference recording sheet is transported by the transport mechanism at the predetermined time point so that the back side surface is a printing surface, the recording sheet other than the reference recording sheet has a front side surface as a printing surface. And the required drive amount of the transport mechanism required in each case of transporting the recording paper so that the back side of the recording paper is the printing surface, and the reference recording paper at the predetermined time point. It is a step of acquiring a value indicating a deviation amount from the required drive amount of the transport mechanism required when transporting so that the front side surface becomes a printing surface, and storing it as the correction data,
In the measurement step, a value related to a deviation amount from the predetermined time point of a required drive amount of a transport mechanism necessary for transporting the reference recording sheet at the present time by the set feed amount using the front side as a printing surface is used. Measuring process,
The control step is based on the type of recording paper detected in the type detection step based on the correction data stored in the data storage unit and the value measured in the measurement step. A conveyance adjustment method for a printer, characterized in that it is a step of controlling the driving amount of the conveyance mechanism so that the feeding amount of the recording paper becomes the set feeding amount according to the determination result in the front / back determination step. In the conveyance adjustment method of the printer according to claim 1 or 2,
The transport mechanism includes at least one transport roller pair that sandwiches and transports the recording paper between a driving roller and a driven roller.
The printer transport adjustment method, wherein the control step is a step of controlling a rotation amount of the drive roller as a drive amount of the transport mechanism.

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