Locating method of an optical sensor, an adjustment method of dot printing position using the optical sensor, and a printing apparatus

A printing registration method for performing printing registration in a first printing operation and a second printing operation of a printing apparatus that prints an image by said first printing operation and said second printing operation with predetermined conditions of a dot forming position on a printing medium by using a printing head, said method comprising the steps of:

• pattern-forming for controlling said printing head to form a plurality of patterns respectively having optical characteristics corresponding to a plurality of shifting amounts, said plurality of patterns being respectively formed corresponding to said plurality of shifting amounts of relative printing positions of said first printing operation and said second printing operation, said plurality of patterns being formed by said first printing operation and said second printing operation;
• measuring respective optical characteristics of said plurality of formed patterns by using an optical sensor comprising a light-emitting portion for irradiating said patterns as an object to be measured with light and a photosensing portion for sensing the light reflected on the object to be measured, said optical sensor being located at a position where an output characteristic of the optical sensor is substantially stable with respect to factors of fluctuations at the time of measurement relative to the object to be measured, wherein, the factors of fluctuations are fluctuations in distance between the object to be measured and the optical sensor, and wherein the position at which the optical sensor is located is determined in relation to the distance from the object to be measured and on the basis of an S/N ratio as the output characteristic of the optical sensor;
• and
• acquiring an adjustment value of a dot forming position condition between said first printing operation and said second printing operation on the basis of respective optical characteristics of said plurality of patterns measured.

A printing apparatus for performing printing of an image on a printing medium by using a printing head, said printing apparatus comprising:

• means for measuring an object by using an optical sensor comprising a light-emitting portion for irradiating the object to be measured with light and a photosensing portion for sensing the light reflected on the object to be measured;
• and
• means for locating said optical sensor at a position where an output characteristic of the optical sensor is substantially stable with respect to factors of fluctuations at the time of measurement relative to the object to be measured,
• wherein, the factors of fluctuations are fluctuations in distance between the object to be measured and the optical sensor;
• and
• wherein, the position at which the optical sensor is located is determined in relation to the distance from the object to be measured and on the basis of an S/N ratio as the output characteristic of the sensor.

A printing apparatus for performing printing of an image by a first printing operation and a second printing operation with predetermined conditions of a dot forming position on a printing medium by using a printing head, said printing apparatus comprising:

• pattern-forming means for controlling said printing head to form a plurality of patterns respectively having optical characteristics corresponding to a plurality of shifting amounts, said plurality of patterns being respectively formed corresponding to said plurality of shifting amounts of relative printing positions of said first printing operation and said second printing operation, said plurality of patterns being formed by said first printing operation and said second printing operation;
• means for measuring respective optical characteristics of said plurality of formed patterns by using an optical sensor comprising a light-emitting portion for irradiating said pattern as an object to be measured with light and a photosensing portion for sensing the light reflected on the object to be measured, said optical sensor being located at a position where an output characteristic of the optical sensor is substantially stable with respect to factors of fluctuations at the time of measurement relative to the object to be measured, wherein, the factors of fluctuations are fluctuations in distance between the object to be measured and the optical sensor, and wherein, the position at which the optical sensor is located is determined in relation to the distance from the object to be measured and on the basis of an S/N ratio as the output characteristic of the optical sensor;
• and
• means for acquiring an adjustment value of a dot forming position condition between said first printing operation and said second printing operation on the basis of respective optical characteristics of said plurality of patterns measured.

A printing system provided with a printing apparatus for performing printing of an image by a first printing operation and a second printing operation with predetermined conditions of a dot forming position on a printing medium by using a printing head, and a host apparatus for supplying image data to said printing apparatus, comprising:

• pattern-forming means for controlling said printing head to form a plurality of patterns respectively having optical characteristics corresponding to a plurality of shifting amounts, said plurality of patterns being respectively formed corresponding to said plurality of shifting amounts of relative printing positions of said first printing operation and said second printing operation, said plurality of patterns being formed by said first printing operation and said second printing operation;
• means for measuring respective optical characteristics of said plurality of formed patterns by using an optical sensor comprising a light-emitting portion for irradiating said pattern as an object to be measured with light and a photosensing portion for sensing the light reflected on the object to be measured, said optical sensor being located at a position where an output characteristic of the optical sensor is substantially stable with respect to factors of fluctuations at the time of measurement relative to the object to be measured, wherein, the factors of fluctuations are fluctuations in distance between the object to be measured and the optical sensor, and wherein, the position at which the optical sensor is located is determined in relation to the distance from the object to be measured and on the basis of an S/N ratio as the output characteristic of the optical sensor;
• and
• means for acquiring an adjustment value of a dot forming position condition between said first printing operation and said second printing operation on the basis of respective optical characteristics of said plurality of patterns measured.