Abstract: An upstream drive roller transports an elongate medium. An upstream tension sensor detects tension of the medium. A downstream drive roller transports the medium. A downstream tension sensor detects tension of the medium in a position between the upstream and downstream drive rollers. A control unit controls transportation of the medium by operating the upstream drive roller based on a first difference which is a difference between a first detection value and a target value, operating the downstream drive roller based on a second difference which is a difference between a second detection value and a target value, and when a specific condition is satisfied, further operating the downstream driver roller with an adjustment value, which is based on the first difference, added to the second difference.

Abstract: A transport control method for use in transporting a medium in a predetermined direction by an upstream drive roller and a downstream drive roller, to operate the downstream drive roller by using PID control based on a detection value of a tension sensor disposed downstream of the upstream drive roller and upstream of the downstream drive roller for detecting tension. The transport control method includes a stable state determining step for determining, at time of the operation, whether a difference between the detection value of the tension sensors and a target value is within a stable width to make a stable state which maintains a stability time; and a gain decreasing step for decreasing a gain of the PID control to be less than an initial value when the difference is determined to be in the stable state.

Abstract: Provided is an inkjet printing apparatus including a first transport roller disposed on a transport path transporting a long print medium, a second transport roller disposed on the transport path downstream of the first transport roller, a print medium holder disposed downstream of the second transport roller, and a recording unit discharging ink droplets to a printing area of the print medium, and performing recording operation, the print medium being transported on the transport path. The first transport roller has a first winding angle upon contact to the print medium. The second transport roller has a second winding angle upon contact to the print medium. The first winding angle is larger than the second winding angle. The first winding angle is equal to or more than 75 degrees. The sum of the first and second winding angles is equal to or more than 80 degrees.

Abstract: A rotary encoder correcting method for a transport apparatus having a rotary encoder for outputting output signals in response to rotation of a transport roller. The method includes the steps of setting beforehand the number of n-divided output signals obtained by dividing, by n, the number of output signals outputted from the rotary encoder with one rotation of the transport roller; measuring a divided area shift time for each divided area when a printing medium is transported at constant speed and each time the number of output signals agrees with the number of n-divided output signals; and calculating a correction coefficient for each divided area based on the divided area shift time. The divided area shift time is corrected for each divided area of the rotary encoder based on each correction coefficient when a process is carried out on the printing medium.

Abstract: An upstream drive roller transports an elongate medium. An upstream tension sensor detects tension of the medium. A downstream drive roller transports the medium. A downstream tension sensor detects tension of the medium in a position between the upstream and downstream drive rollers. A control unit controls transportation of the medium by operating the upstream drive roller based on a first difference which is a difference between a first detection value and a target value, operating the downstream drive roller based on a second difference which is a difference between a second detection value and a target value, and when a specific condition is satisfied, further operating the downstream driver roller with an adjustment value, which is based on the first difference, added to the second difference.

Abstract: A rotary encoder correcting method for a transport apparatus having a rotary encoder for outputting output signals in response to rotation of a transport roller. The method includes the steps of setting beforehand the number of n-divided output signals obtained by dividing, by n, the number of output signals outputted from the rotary encoder with one rotation of the transport roller; measuring a divided area shift time for each divided area when a printing medium is transported at constant speed and each time the number of output signals agrees with the number of n-divided output signals; and calculating a correction coefficient for each divided area based on the divided area shift time. The divided area shift time is corrected for each divided area of the rotary encoder based on each correction coefficient when a process is carried out on the printing medium.

Abstract: Provided is a printing method of performing printing onto a recording medium to be transported with a plurality of recording element arrays. The printing method includes a storing step of storing a perimeter of a timing roller upon acquiring correction data in association with the correction data, an obtaining step of obtaining the perimeter during printing after the storing step of storing the perimeter upon acquiring the correction data, and a modifying step of modifying the correction data during the printing in accordance with the perimeter upon acquiring the correction data and the perimeter during the printing.

Abstract: Disclosed is a printing apparatus that performs printing onto a print medium including a transporting device that transports a print medium, a plurality of printing heads, a photographing unit that photographs the print medium, a shift detecting chart forming device, and a correcting device. The shift detecting chart forming device forms a shift detecting chart having a first line segment group consisting of first line segments that are printed onto the print medium at given intervals in an orthogonal direction with respect to the transportation direction with a reference printing head, and a second line segment group formed along the first line segment group, and consisting of second line segments that are printed with a subsequent printing head. The correcting device corrects a printing timing with the subsequent printing head relative to the reference printing head in accordance with a density variation of the photographed shift detecting chart.

Abstract: Disclosed is a printing apparatus that performs printing onto a print medium including a transporting device that transports a print medium, a plurality of printing heads, a photographing unit that photographs the print medium, a shift detecting chart forming device, and a correcting device. The shift detecting chart forming device forms a shift detecting chart having a first line segment group consisting of first line segments that are printed onto the print medium at given intervals in an orthogonal direction with respect to the transportation direction with a reference printing head, and a second line segment group formed along the first line segment group, and consisting of second line segments that are printed with a subsequent printing head. The correcting device corrects a printing timing with the subsequent printing head relative to the reference printing head in accordance with a density variation of the photographed shift detecting chart.

Abstract: Disclosed is an inkjet printing apparatus with an inkjet printing unit performing printing onto web paper to be transported. The apparatus includes a drive roller transporting the web paper, a transportation velocity detector detecting a transportation velocity of the web paper, an encoder generating a timing reference signal of the printing by the printing unit in accordance with transportation of the web paper, the encoder being disposed in a transport roller, a printing correction data generator generating printing correction data in accordance with the transportation velocity and the timing reference signal so as to correspond to a time-dependent variation of the transport roller provided with the encoder; and an offset corrector correcting the printing of the inkjet printing unit to the web paper in accordance with the printing correction data.

Abstract: Provided is a printing method of performing printing onto a recording medium to be transported with a plurality of recording element arrays. The printing method includes a storing step of storing a perimeter of a timing roller upon acquiring correction data in association with the correction data, an obtaining step of obtaining the perimeter during printing after the storing step of storing the perimeter upon acquiring the correction data, and a modifying step of modifying the correction data during the printing in accordance with the perimeter upon acquiring the correction data and the perimeter during the printing.

Abstract: Provided is an inkjet printing apparatus including a first transport roller disposed on a transport path transporting a long print medium, a second transport roller disposed on the transport path downstream of the first transport roller, a print medium holder disposed downstream of the second transport roller, and a recording unit discharging ink droplets to a printing area of the print medium, and performing recording operation, the print medium being transported on the transport path. The first transport roller has a first winding angle upon contact to the print medium. The second transport roller has a second winding angle upon contact to the print medium. The first winding angle is larger than the second winding angle. The first winding angle is equal to or more than 75 degrees. The sum of the first and second winding angles is equal to or more than 80 degrees.

Abstract: Disclosed is an inkjet printing apparatus with an inkjet printing unit performing printing onto web paper to be transported. The apparatus includes a drive roller transporting the web paper, a transportation velocity detector detecting a transportation velocity of the web paper, an encoder generating a timing reference signal of the printing by the printing unit in accordance with transportation of the web paper, the encoder being disposed in a transport roller, a printing correction data generator generating printing correction data in accordance with the transportation velocity and the timing reference signal so as to correspond to a time-dependent variation of the transport roller provided with the encoder; and an offset corrector correcting the printing of the inkjet printing unit to the web paper in accordance with the printing correction data.

Abstract: A printing apparatus for performing printing under control of a head controller which receives image data, and which is connected to a print head for printing. The head controller includes an image data shaping unit for shaping the image data into print data corresponding to the print head, a sequence information generating unit for generating sequence information, based on the print data, showing operation at a time of printing by the print head, a data guarantee information adding unit for adding data guarantee information to the print data and the sequence information, for error detection based on the print data and the sequence information, a readout unit for reading print information including the print data, the sequence information, and the data guarantee information, and an information inspecting unit for inspecting propriety of the print information based on the data guarantee information and the sequence information read by the readout unit.

Abstract: A printing apparatus for performing printing under control of a head controller which receives image data, and which is connected to a print head for printing. The head controller includes an image data shaping unit for shaping the image data into print data corresponding to the print head, a sequence information generating unit for generating sequence information, based on the print data, showing operation at a time of printing by the print head, a data guarantee information adding unit for adding data guarantee information to the print data and the sequence information, for error detection based on the print data and the sequence information, a readout unit for reading print information including the print data, the sequence information, and the data guarantee information, and an information inspecting unit for inspecting propriety of the print information based on the data guarantee information and the sequence information read by the readout unit.

Abstract: In an image recording apparatus, shift times for shifting switching timings of light modulator elements are obtained so that rise times (U1) after input of output start signals to driving elements connected to respective light modulator elements of a spatial light modulator and fall times (D1) after input of output stop signals become a constant target rise time (U2) and a constant target fall time (D2). This makes it possible to suppress unevenness of the rise times and the fall times after correction of light amounts even if light modulator elements where the rise times and the fall times change by correction of light amounts are used and consequently, an image can be appropriately recorded without a complicate apparatus.

Abstract: In each light modulator element of a special light modulator with diffraction grating structure where moving ribbons and fixed ribbons are alternately arranged, the maximum light-amount (I1) when an output light-amount first becomes maximum from when the moving ribbons start to sag and the maximum light amount-voltage becoming an displacement amount (P1) at the maximum light-amount, are obtained and the minimum of a plurality of maximum light-amounts is set as a target ON light-amount (It). Since a voltage (corresponding to a displacement amount (Pt1)) between the maximum light amount-voltage and the minimum light amount-voltage at a displacement amount (P2) is obtained as a target ON-voltage for the target ON light-amount (It), it is thereby possible to prevent moving distance of the moving ribbons among ON/OFF from largely differing among the light modulator elements and achieve an appropriate image recording.

Abstract: In each light modulator element of a special light modulator with diffraction grating structure where moving ribbons and fixed ribbons are alternately arranged, the maximum light-amount (I1) when an output light-amount first becomes maximum from when the moving ribbons start to sag and the maximum light amount-voltage becoming an displacement amount (P1) at the maximum light-amount, are obtained and the minimum of a plurality of maximum light-amounts is set as a target ON light-amount (It). Since a voltage (corresponding to a displacement amount (Pt1)) between the maximum light amount-voltage and the minimum light amount-voltage at a displacement amount (P2) is obtained as a target ON-voltage for the target ON light-amount (It), it is thereby possible to prevent moving distance of the moving ribbons among ON/OFF from largely differing among the light modulator elements and achieve an appropriate image recording.

Abstract: The inventive image recording apparatus records unit images with different combinations of light beams among a plurality of light beams emissive from a recording head when preparing the respective ones of C, M, Y and K plates. Also when the plurality of light beams are dispersed in quantity of light, therefore, density distributions of different tendencies result in the unit images recorded on the respective ones of the C, M, Y and K plates. In a resultant image formed by superposing the unit images with each other, therefore, fluctuation of densities can be canceled and reduced.

Abstract: The inventive image recording apparatus records unit images with different combinations of light beams among a plurality of light beams emissive from a recording head when preparing the respective ones of C, M, Y and K plates. Also when the plurality of light beams are dispersed in quantity of light, therefore, density distributions of different tendencies result in the unit images recorded on the respective ones of the C, M, Y and K plates. In a resultant image formed by superposing the unit images with each other, therefore, fluctuation of densities can be canceled and reduced.