Abstract: An image recording apparatus 1 generates halftone image data regarding black, cyan, magenta, and yellow from a multi-tone color image. Magenta is a target color component that has a lower ink density than that of the other color components. In generating halftone image data regarding magenta, the sum of the sizes of black, cyan, and magenta dots formed at a target pixel position is made smaller than or equal to a threshold dot size. If the hue of the pixel of interest is within a hue range in which magenta coloration is strong, it is determined that the threshold dot size is a corrected threshold dot size larger than the reference threshold dot size. It is thus possible to suppress overlapping of dots of a plurality of color components and to thereby improve color reproduction of the target color component while suppressing poor color reproduction and cockling.

Abstract: In the generation of a threshold matrix for N× speed writing, first and second areas are set, the first area being a cluster of a plurality of first partial areas substantially evenly distributed in a matrix space, and the second area being an area of the matrix space excluding the first area. Next, at least two writing elements in each of the first partial areas are allocated occurrence numbers and changed into determined elements. Then, at least one writing element in the second area is allocated an occurrence number and changed into a determined element. Thereafter, the other writing elements are allocated occurrence numbers and changed into determined elements. In accordance with the occurrence numbers, the threshold value of each writing element is determined to obtain a threshold matrix for N× speed writing. This results in a reduction in the graininess of an image in a highlight area.

Abstract: An image obtained by shrinking an original image in a row direction is halftoned, and this halftone dot image is enlarged in the row direction and recorded at double speed. In order to determine a threshold value of a threshold matrix used for halftoning an image, prepared is a matrix space in accordance with writing positions used for actual recording of an image. In the matrix space, writing elements are set alternately with non-writing elements both in the row direction and in a column direction. In the matrix space, turn-on numbers are allocated to all the writing elements in avoidance of the non-writing elements. Then, in accordance with the turn-on numbers, respective threshold values for the writing elements are determined. By shrinking the threshold matrix in the row direction with omission of the non-writing elements, a threshold matrix for double speed is obtained.

Abstract: A torque damper apparatus including a multiple disc clutch lock-up clutch, damper springs arranged for damping variation of the torque transmitted via a hub gear, an urging member connected to the hub gear a fastener, and a torque transmitting member for holding the damper springs and outputting the torque transmitted from the urging member via the damper springs. The torque transmitting member can be formed with windows receiving the fastener. The hub gear and the urging member can be fastened together by the fastener within the windows.

Abstract: An image recording apparatus generates black, cyan, magenta, and yellow halftone image data from a multi-tone color image. When the cyan halftone image data is generated, the size of a cyan dot to be formed at a target pixel position is provisionally determined and added to the size of a black dot to obtain a total dot size. When the total dot size is less than or equal to a first threshold dot size, the cyan dot size is determined to be the provisionally determined size, and when the total dot size is greater than the first threshold dot size, the cyan dot size is determined to be the largest dot size within the range of a difference between the first threshold dot size and the black dot size. It is possible to prevent excessive overlapping of black and cyan dots.

Abstract: A threshold matrix generation part determines a turn-on order in a matrix area where a threshold matrix is generated and determines a threshold value of each matrix element. In determining the turn-on order, a temporary evaluation value element is obtained based on a distance between each undetermined matrix element whose position in the turn-on order has not been determined and each determined matrix element. If these matrix elements are located in the same position with respect to a row or column direction, the temporary evaluation value element is corrected such that the undetermined matrix element is less evaluated based on the evaluation value. Then, the position of an undetermined matrix element that is most highly evaluated in the turn-on order is determined. Accordingly, a threshold matrix that suppresses the occurrence of a grid-like dot pattern can be provided.

Abstract: An image recording apparatus has low intensity ink ejection parts for ejecting low intensity ink, and a high intensity ink ejection part for ejecting high intensity ink. With respect to a direction orthogonal to a moving direction of printing paper, a pitch of outlets in the high intensity ink ejection part is larger than that in the low intensity ink ejection part. Thus, manufacturing cost of the apparatus is reduced. With respect to each gray level in a middle grayscale range, if a tint image is recorded with the high intensity ink, a spatial frequency of this tint image is lower than that of a tint image recorded with the low intensity ink. By the above image recording control, even if the high intensity ink ejection part includes an abnormal outlet where a flight direction of droplet is abnormal, streak unevenness in a color halftone image can be suppressed.

Abstract: An image recording apparatus generates black, cyan, magenta, and yellow halftone image data from a multi-tone color image. When the cyan halftone image data is generated, the size of a cyan dot to be formed at a target pixel position is provisionally determined and added to the size of a black dot to obtain a total dot size. When the total dot size is less than or equal to a first threshold dot size, the cyan dot size is determined to be the provisionally determined size, and when the total dot size is greater than the first threshold dot size, the cyan dot size is determined to be the largest dot size within the range of a difference between the first threshold dot size and the black dot size. It is possible to prevent excessive overlapping of black and cyan dots.

Abstract: In an image recording apparatus, only small ink droplets are ejected toward a recording medium in the range of tone values less than a second tone value. In the range of tone values greater than or equal to the second tone value and less than a first tone value, large and small droplets are ejected toward the recording medium. The first tone value is less than or equal to a 50% tone value, and the total ejection rate at the first tone value is less than 50%. In the range of tone values greater than or equal to the first tone value, only large droplets are ejected toward the recording medium. Thus, the occurrence of streaking can be suppressed while reducing the degree of instability of the landing positions of fine droplets of ink.

Abstract: A threshold matrix generation part determines a turn-on order in a matrix area where a threshold matrix is generated and determines a threshold value of each matrix element. In determining the turn-on order, a temporary evaluation value element is obtained based on a distance between each undetermined matrix element whose position in the turn-on order has not been determined and each determined matrix element. If these matrix elements are located in the same position with respect to a row or column direction, the temporary evaluation value element is corrected such that the undetermined matrix element is less evaluated based on the evaluation value. Then, the position of an undetermined matrix element that is most highly evaluated in the turn-on order is determined. Accordingly, a threshold matrix that suppresses the occurrence of a grid-like dot pattern can be provided.

Abstract: A connector, which can protect a photoelectric conversion device from noise and has high durability includes a plug provided at one end of an optical fiber and a receptacle to which the plug is mounted from above. The plug includes a photoelectric conversion device composed of a semiconductor device that is not covered with a metal case and a metal member provided so as to cover an upper side of the photoelectric conversion device. The receptacle includes a metal housing to which the plug is fixed. The plug and the receptacle are fixed to each other only by engagement between the metal member and the metal housing.

Abstract: In a matrix area, a plurality of linear areas each of which extends in a tilt direction tilted relatively to row and column directions are arranged in a direction perpendicular to the tilt direction without spaces, and the plurality of linear areas are alternatively assigned to first and second element groups along an arrangement direction. One element is specified in each element group, and subsequently a process of specifying an element farthest from the specified elements is repeated, to acquire a turn-on order of dots with increase in gray level in one grayscale range and a turn-off order of dots with decrease in gray level in the remaining grayscale range, and a threshold value of each element is determined according to these orders. Thus, generated is a threshold matrix capable of reducing graininess in a halftone image with directionality in the tilt direction, and improving the reproduction of thin lines and characters.

Abstract: In a matrix area, a plurality of linear areas each of which extends in a tilt direction tilted relatively to row and column directions are arranged in a direction perpendicular to the tilt direction without spaces, and the plurality of linear areas are alternatively assigned to first and second element groups along an arrangement direction. One element is specified in each element group, and subsequently a process of specifying an element farthest from the specified elements is repeated, to acquire a turn-on order of dots with increase in gray level in one grayscale range and a turn-off order of dots with decrease in gray level in the remaining grayscale range, and a threshold value of each element is determined according to these orders. Thus, generated is a threshold matrix capable of reducing graininess in a halftone image with directionality in the tilt direction, and improving the reproduction of thin lines and characters.

Abstract: In a matrix area, a plurality of linear areas each of which extends in a tilt direction tilted relatively to row and column directions are arranged in a direction perpendicular to the tilt direction without spaces, and the plurality of linear areas are alternatively assigned to first and second element groups along an arrangement direction. One element is specified in each element group and subsequently process of specifying an element farthest from specified elements, is repeated to acquire a turn-on order of dots with increase in gray level in one grayscale range and a turn-off order of dots with decrease in gray level in the remaining grayscale range, and a threshold value of each element is determined according to these orders. Thus, generated is a threshold matrix capable of reducing graininess in a halftone image with directionality in the tilt direction, and improving the reproduction of thin lines and characters.

Abstract: An image recording apparatus has low intensity ink ejection parts for ejecting low intensity ink, and a high intensity ink ejection part for ejecting high intensity ink. With respect to a direction orthogonal to a moving direction of printing paper, a pitch of outlets in the high intensity ink ejection part is larger than that in the low intensity ink ejection part. Thus, manufacturing cost of the apparatus is reduced. With respect to each gray level in a middle grayscale range, if a tint image is recorded with the high intensity ink, a spatial frequency of this tint image is lower than that of a tint image recorded with the low intensity ink. By the above image recording control, even if the high intensity ink ejection part includes an abnormal outlet where a flight direction of droplet is abnormal, streak unevenness in a color halftone image can be suppressed.

Abstract: The low and high occupancy rate matrix sets are stored in the inkjet printer which performs printing with dots having different sizes. For the original image where banding unevenness easily appears, used is the low occupancy rate matrix set where the occupancy rate of all dots is lower than 100% in the maximum value of gray level and the proportion of the large dots is high in a high range of gray level. For the original image where reproducibility of details is required, used is the high occupancy rate matrix set where the occupancy rate of all dots becomes 100% in a value of gray level lower than the maximum value of gray level and the proportion of the small dots is high in a middle range of gray level. It is therefore possible to perform appropriate printing in accordance with the classification of the original image.

Abstract: Each of moire elements which are repeat elements of first-order moire appearing by overlaying halftone images of first and second color components is positioned at one of candidate positions arranged at a moire pitch Pm in first and second moire directions orthogonal to each other. In a matrix area of a third color component, dot centers are arranged in a first tilt direction tilted relatively to the first moire direction by an angle of arctan((Pm)/(Pm)) and a second tilt direction orthogonal to the first tilt direction at a pitch of the square root of ((Pm2)+(Pm2)), and a threshold matrix of the color component is generated so that a halftone dot grows from each dot center in accordance with increase of gray level of the color component of the original image. Thus, it is possible to suppress second-order moire appearing in overlaying halftone images of the first to third color components.

Abstract: In a halftone image formed on a printing plate for letterpress printing, a minimum halftone dot has a square main cluster consisting of 9 pixels and four sub-clusters located around the main cluster radially, each of which is one pixel. Each sub-cluster contacts with only a vertex of the main cluster. Convex portions corresponding to the minimum halftone dots in the halftone image are formed on the printing plate. A convex portion corresponding to the main cluster is supported by convex portions corresponding to the sub-clusters to increase the strength of relief corresponding to the minimum halftone dot. Reliefs corresponding to the minimum halftone dots are normally formed regardless of a dot area rate of highlight area to thereby improve reproduction in printing of the halftone image.

Abstract: A head in a printer has an outlet row including a plurality of outlets arranged in a width direction perpendicular to a scan direction. A threshold matrix is stored in a main body control part, and sleep elements representing sleep of ejection of ink are arranged in the threshold matrix at a regular interval in each element row which is a plurality of elements arranged in a row direction corresponding to the width direction. The threshold matrix is compared with a grayscale original image to generate data of a halftone image where during printing, the number of outlets included in each outlet group not brought into sleep state continuously in the width direction is made equal to or larger than 1 and equal to or smaller than a predetermined number. Thus, it is possible to easily suppress occurrence of unevenness in a printed image, caused by cross talk between outlets.

Abstract: An ejection part (3) in an inkjet printer (1) has ejection mechanisms (31a to 31d) for ejecting fine droplets of colored ink and an ejection mechanism (32) for ejecting fine droplets of clear ink, and a colored image is formed on a colored image print area of print medium (9) by the ejection mechanisms (31a to 31d). By the ejection mechanism (32), the colored image on the print medium (9) is coated with the clear ink and a code image is formed on a blank area around the colored image print area. In the inkjet printer (1), since the coating of the colored image and the forming of the code image are performed with the same clear ink ejected from the one ejection mechanism (32), improvement of wear resistance and improvement of security of the colored image can be achieved while reducing manufacturing cost of the apparatus of the inkjet printer (1).