JP2007062284A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the quality of a printed material in an image forming apparatus. <P>SOLUTION: Positions of thermal heads 71a, 72a in a direction perpendicular to a conveyance direction are adjusted based on the position of one end of a paper sheet P in a direction perpendicular to the conveyance direction, which is detected by means of a paper detection sensor 90 in the printing of a color image on the paper sheet P, by referencing the position of a thermal head 73a in the direction perpendicular to the conveyance direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus.

  Various techniques are known for image forming apparatuses that form images on printed paper (see, for example, Patent Documents 1 to 3).

  Patent Document 1 includes three thermal heads that can print yellow, magenta, and cyan, respectively, and the recording paper drawn from the recording paper roll is transported in the paper feeding direction, and color images are printed by these thermal heads. A one-pass color thermal printer that forms the image is disclosed.

Patent Document 2 includes three thermal heads capable of printing yellow, magenta, and cyan, respectively, and after the recording paper drawn from the recording paper roll is conveyed in the paper feeding direction and preparation for image formation is completed. A one-pass color thermal printer that forms a color image of one frame while conveying the recording paper in the pull-back direction is disclosed. In this printer, when a color image of one frame is formed, the recording paper is conveyed again in the paper feeding direction and cut at the rear end portion of the color image. Thereafter, the recording paper on which the color image is formed is discharged, and the next one-frame color image is formed while conveying the recording paper that has been prepared for image formation in the pull-back direction.
Japanese Patent Application Laid-Open No. 8-174476 JP 2001-246769 A

  However, in the image forming apparatus as described above, when the recording paper on which the color image is being formed is skewed, the recording start position in the direction perpendicular to the transport direction of each thermal head with respect to the recording paper is shifted, and the quality of the printed matter There was a risk of deterioration. In particular, in the method of forming a color image with a thermal head while transporting the recording paper for a plurality of images in the feeding direction and winding the recording paper in the retracting direction, The skew of the recording paper during forming is a big problem, and the above-mentioned problems are remarkable.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an image forming head for forming an image on a print paper being conveyed, and the print paper is formed by the image forming head. An object of the present invention is to provide a technique for improving the quality of printed matter in an image forming apparatus that forms a desired image by forming the image.

  According to a first aspect of the present invention, an image forming head for forming an image on a print paper being conveyed is provided, and a desired image is formed by forming the image on the print paper by the image forming head. An image forming apparatus comprising: a detection unit that detects a position of an end of a paper in a paper transport orthogonal direction perpendicular to the paper transport direction in the print paper during formation of a desired image; and during formation of a desired image on the print paper, An adjustment unit that adjusts the image formation start position of the image forming head in the paper conveyance orthogonal direction based on the position of the end of the print paper in the paper conveyance orthogonal direction detected by the detection unit. It is a feature.

  As a result, during the formation of the desired image on the print paper by the adjustment unit, the paper transport orthogonal direction of the image forming head is detected based on the position of the end of the print paper in the paper transport orthogonal direction. Since the image formation start position is adjusted, it is possible to suppress the deviation of the image formation start position in the direction perpendicular to the paper conveyance with respect to the print paper of the image formation head even when the print paper during formation of a desired image is skewed. Therefore, the quality of printed matter can be improved.

  According to a second aspect of the present invention, in the first aspect, the image forming head is a plurality of image forming heads for forming images on the print paper being conveyed. A desired image is formed by superimposing the respective images on the paper, and the adjusting unit is detected by the detecting unit during formation of the desired image on the printed paper. Further, the image forming start position of at least one of the plurality of image forming heads in the paper transport orthogonal direction is adjusted based on the position of the end of the print paper in the paper transport orthogonal direction. It is characterized by being.

  Accordingly, at least one of the plurality of image forming heads based on the position of the end of the print paper in the direction perpendicular to the paper conveyance detected by the detection unit during formation of a desired image on the print paper by the adjustment unit. Since the image formation start position of the two image forming heads in the direction perpendicular to the paper conveyance is adjusted, even if the print paper forming the desired image is skewed, the image in the direction perpendicular to the paper conveyance with respect to the print paper of each image formation head The formation start position can be prevented from shifting. Therefore, the occurrence of color misregistration for each color can be suppressed. Therefore, the quality of printed matter can be improved.

  In a third aspect based on the second aspect, the image forming heads are arranged in order in the paper transport direction, and form color images of different colors on the print paper being transported. The image forming head is configured to form a desired color image by superimposing the color images on the print paper by the image forming heads. is there.

  As a result, a desired color image is formed on the printed paper being transported, and the quality of the printed matter of the color image can be improved.

  In a fourth aspect based on the third aspect, the adjusting section detects an end of the print paper in a direction perpendicular to the paper conveyance direction detected by the detection section during formation of a desired color image on the print paper. Based on the position, an image in the paper transport orthogonal direction of the other image forming heads with reference to the image formation start position in the paper transport orthogonal direction of the upstreammost image forming head in the paper transport direction among the plurality of image forming heads The present invention is characterized in that the formation start position is adjusted.

  As a result, the adjustment unit detects the paper among the plurality of image forming heads based on the position of the end of the print paper in the direction perpendicular to the paper conveyance detected during the formation of the desired color image on the print paper. All image forming heads adjust the image forming start position in the paper transport orthogonal direction of the other image forming heads with reference to the image forming start position in the paper transport orthogonal direction of the most upstream image forming head in the transport direction. There is no need to adjust the image formation start position in the direction perpendicular to the paper conveyance. Therefore, the adjustment of the image formation start position of the image forming head in the paper conveyance orthogonal direction can be simplified as compared with the case of adjusting the image formation start position of the image formation head in the paper conveyance orthogonal direction.

  According to the present invention, during the formation of a desired image on a print paper, the image formation start position in the paper transport orthogonal direction of the image forming head is adjusted based on the position of the end of the print paper in the paper transport orthogonal direction. Even if the print paper in which a desired image is being formed is skewed, it is possible to prevent the image formation start position of the image forming head from shifting in the direction perpendicular to the paper conveyance with respect to the print paper. Therefore, the quality of printed matter can be improved.

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

  FIG. 1 is a perspective view of a thermal sublimation thermal printer (hereinafter referred to as a printer) 1 according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of a printing unit 30, and FIG. FIG. 4 is a plan view of the head unit 73 and the paper detection sensor 90, and FIG. 5 is a side view of the thermal head 73a and the lifting mechanism 73l. FIG. 6 is a plan view of the paper detection sensor 90.

  As shown in FIG. 1, the printer 1 includes an operation unit 10, a control device 20, and a printing unit 30. The operation unit 10 is for an operator to operate the printer 1 and has a display 11 for displaying various information about the printer 1 and notifying the operator. Here, in the present embodiment, a touch panel method is adopted for the operation unit 10, and an operation screen 12 including various buttons is displayed on the display 11. Therefore, the operator can operate the printer 1 by touching the operation screen 12.

  The control device 20 receives input from the operation unit 10 and controls various operations of the printer 1. The control device 20 has a plurality of data input units 20a for acquiring print data from various storage media such as a card slot and a disk drive. The recording medium may be any recording medium that can store print data, such as a CD-ROM or a memory card.

  The operation unit 10 and the control device 20 are fixedly arranged on the upper surface of a housing 30 a that houses the print unit 30. The display surface of the display 11 of the operation unit 10 and the storage medium insertion surface of the data input unit 20a of the control device 20 substantially coincide with the front of the printer 1 (housing 30a) (the surface on the left front side in FIG. 1). Therefore, it is easy for an operator heading to the front of the printer 1 to operate the display 11 and the data input unit 21.

  The housing 30a is formed in a substantially rectangular parallelepiped shape, and its lateral width (front width) D1 is smaller than the depth D2. Therefore, the printer 1 can be installed even in a relatively narrow space.

  As shown in FIG. 2, the printing unit 30 includes a paper supply unit 40 that holds printing paper (print paper; hereinafter referred to as paper) P wound in a roll shape in a housing 30 a, and a paper supply unit 40. A paper take-up unit 80 that takes up the paper P that has been unwound from the paper, and a transport mechanism 38 that can transport the paper P along a transport path curved upward between the paper supply unit 40 and the paper take-up unit 80. And have. Between the paper supply unit 40 and the paper winding unit 80, a cutting unit 50, an overcoat unit 60, and a printing unit 70 are arranged from the upstream side to the downstream side of the conveyance path. A discharge unit 95 is provided in the vicinity of the conveyance path between the paper supply unit 40 and the cutting unit 50.

  In the present embodiment, “the transport direction (transport direction) of the paper P” refers to a direction from the paper supply unit 40 toward the paper winding unit 80. The “backward feeding direction of the paper P” means a direction from the paper winding unit 80 toward the paper supply unit 40. “The leading edge of the paper P” and “the leading edge of the image” mean the downstream edge in the transport direction of the paper P and the image. The “rear end portion of the sheet P” and the “rear end portion of the image” mean the upstream end portion in the transport direction of the sheet P and the image.

  The paper supply unit 40 has a magazine case 41 provided in the uppermost stream of the transport path, and in the magazine case 41, a long paper P is arranged around the rotation shaft 43 so that its printing surface is on the outer side. A wound winding part 45 is loaded. The rotation shaft 43 is driven to rotate counterclockwise as shown in FIG. 2 when the paper P is unwound from the paper supply unit 40 and conveyed toward the downstream side in the conveyance direction by the motor 43a (see FIG. 3). When the unrolled paper P is taken up by the paper supply unit 40, it is driven to rotate clockwise as shown in FIG.

  The transport mechanism 38 includes a pair of paper feed rollers 31 that are sequentially disposed from the upstream side in the transport direction and can transport the paper P unrolled from the winding unit 45 of the paper supply unit 40 upward, and the cutting unit 50. Is also arranged on the upstream side in the transport direction, and the turn roller pair 32 that changes the transport direction of the paper P that is transported upward, and the crimping that can sandwich the paper P between the cutting unit 50 and the overcoat unit 60 The roller pair 33 and the transport roller pair 34 that can transport the paper P, and the paper P that is disposed downstream of the printing unit 70 in the transport direction and transported downstream of the printing unit 70 in the transport direction. A feed roller pair 35 for feeding into the inside of the section 80 is provided.

  The pair of feed rollers 31, the pair of turn rollers 32, the pair of pressure rollers 33, the pair of transport rollers 34, and the pair of feed rollers 35 are along a circumference having a predetermined radius (indicated by a two-dot chain line in FIG. 2). Are arranged in order. As can be seen from FIG. 2, the head portions 61 and 71 to 73 of the overcoat unit 60 and the printing unit 70 are also arranged in order along the circumference, and the paper supply unit 40 and the paper winding unit. 80 is arranged inside the circumference. In other words, the head portions 61 and 71 to 73 of the overcoat unit 60 and the printing unit 70 are arranged in tandem from the upstream side in the transport direction.

  The paper feed roller pair 31, the transport roller pair 34, and the feed roller pair 35 are connected to motors 31a, 34a, and 35a (see FIG. 3) controlled by the transport control unit 27a (see FIG. 3), respectively. . Accordingly, the paper feed roller pair 31, the transport roller pair 34, and the feed roller pair 35 are unrolled from the paper supply unit 40 when the motors 31a, 34a, and 35a are individually controlled by the transport control unit 27a. It is possible to transport P toward the downstream side in the transport direction and wind it around the paper take-up unit 80, and to unwind the paper P once taken up in the paper take-up unit 80, while rewinding the paper take-up unit 80. The paper P that has been unwound from the paper can be fed back toward the upstream side in the transport direction.

  The printing unit 30 includes an encoder 36 that can detect the number of rotations (number of pulses) of the conveyance roller pair 34. The transport roller pair 34 can be driven and rotated by a motor 34 a to transport the paper P, and can be driven and rotated along with the paper P transported by the feed roller pair 35. The encoder 36 can detect the number of rotations of the transport roller pair 34 even when the transport roller 34 is in any of the above states.

  The cutting part 50 is disposed between the turn roller pair 32 and the pressure roller pair 33. The cutting unit 50 includes a rolling cutter 51 disposed above the conveyance path, a fixed blade 52 disposed below the conveyance path, and a chip box 53.

  The rolling cutter 51 is formed in a disk shape, and a blade is formed on the entire circumference of the rolling cutter 51. The center of the rolling cutter 51 is held by a shaft 51a. The rolling cutter 51 is connected to a drive mechanism 55 (see FIG. 3) controlled by the cutting control unit 27c via a shaft 51a. The drive mechanism 55 rotationally drives the rolling cutter 51 via the shaft 51a and reciprocates along a direction orthogonal to the conveyance path of the paper P (in the direction orthogonal to the paper surface in FIG. 2). The fixed blade 52 is a rectangular blade that is disposed so as to be orthogonal to the transport path of the paper P and is longer than the entire width of the transport path of the paper P.

  Therefore, in a state where the paper P is arranged at the cutting position by the cutting unit 50, when the cutting control unit 27 c controls the drive mechanism 55 and rotates the rolling cutter 51 along the width direction of the paper P, The sheet P is cut by the interaction between the rolling cutter 51 and the fixed blade 52. In the present embodiment, the cutting unit 50 cuts the paper P at the leading edge and the trailing edge of each image.

  The chip box 53 is disposed below the rolling cutter 51 and the fixed blade 52. Therefore, when the paper P is cut at the leading edge or the trailing edge of each image and the margin between the images is cut, the margin is stored in the chip box 53.

  The overcoat unit 60 is disposed on the downstream side of the conveyance roller pair 34 in the conveyance direction. The overcoat part 60 has one head part 61. The head unit 61 is for covering the surface of the paper P on which an image is printed with a colorless and transparent overcoat (OC). In this way, by applying the overcoat to the surface of the paper P, the light resistance of the image printed on the paper P can be improved and the surface of the paper P can be protected. Further, by selecting the material of the overcoat, it is possible to improve the gloss of the print and provide a high-quality print.

  In the present embodiment, when the paper P unrolled from the paper supply unit 40 is conveyed toward the downstream side in the conveyance direction, the overcoat in the overcoat unit 60 and the color image printing in the printing unit 70 are performed. First, when the paper P once taken up by the paper take-up unit 80 arranged on the downstream side in the transport direction from the printing unit 70 is fed back toward the upstream side in the transport direction, the color image in the print unit 70 Printing and overcoating in the overcoat unit 60 are performed. Therefore, in this embodiment, it is possible to print a color image in the order of yellow, magenta, and cyan on the surface of the paper P, and further, overcoat the surface of the paper P on which the color image is printed. be able to.

  Hereinafter, the detailed configuration of the head units 61 and 71 to 73 will be described. In addition, since the structure of the head parts 61 and 71 to 73 is almost the same, only the head part 72 will be described in detail here.

  The head unit 72 has a large number of heating elements (not shown) arranged over the entire width of the transport path of the paper P, and is a thermal for printing a color image corresponding to magenta on the paper P being transported. Ink corresponding to magenta adhered to the head 72a (image forming head), the platen roller 72b facing the tip of the thermal head 72a (the end near the paper P conveyance path and where the heating element is disposed), and magenta. It has a tape-like ribbon 72c having an ink region, a ribbon supply roller 72d around which a ribbon 72c before printing is wound, and a ribbon take-up roller 72e that winds up the ribbon 72c after printing.

  As shown in FIG. 4, a head holding shaft 72f that rotatably holds the thermal head 72a is provided at the downstream end of the thermal head 72a in the transport direction. The head holding shaft 72f extends in a direction orthogonal to the conveyance direction of the paper P (width direction of the paper P. paper conveyance orthogonal direction, hereinafter referred to as conveyance orthogonal direction).

  A center plate 72g extending from the head holding shaft 72f to the upstream side in the conveyance direction and a center plate pressing spring 72h are provided at the center of the head holding shaft 72f in the conveyance orthogonal direction to restrict the position of the head holding shaft 72f in the conveyance orthogonal direction. And a pair of retaining rings 72i. The center plate 72g is rotatably attached to the head holding shaft 72f.

  A leaf spring extending in the conveying direction between the both ends of the head holding shaft 72f in the conveyance orthogonal direction and the both ends of the thermal head 72a in the conveyance orthogonal direction in order to regulate the distance between the head holding shaft 72f and the thermal head 72a. Each member 72j is provided. Each leaf spring member 72j is fixed to the head holding shaft 72f and the thermal head 72a with screws.

  A head slide drive mechanism 72k capable of moving the head holding shaft 72f in the conveyance orthogonal direction is provided at one end portion (right end portion in FIG. 4) of the head holding shaft 72f in the conveyance orthogonal direction. Therefore, the thermal head 72a is movable in the conveyance orthogonal direction by the head holding shaft 72f and the head slide drive mechanism 72k.

  As shown in FIG. 5, the thermal head 72a can be moved back and forth with respect to the transport path of the paper P by an elevating mechanism 72l that rotates the head about a head holding shaft 72f and moves it up and down. Therefore, the thermal head 72a can selectively take a print position where the ribbon 72c is pressed (pressed) against the paper P and a retracted position where the ribbon 72c is not pressed between the vicinity of the front end portion and the platen roller 72b.

  The elevating mechanism 72l includes a cam shaft 72m provided above the thermal head 72a, a pressurizing mechanism 72n provided above the camshaft 72m, and a head provided between the thermal head 72a and the pressurizing mechanism 72n. And a release spring 72o. The pressure mechanism 72n includes a motor 72p and a crank 72q that transmits the power of the motor 72p to the camshaft 72m. Therefore, the pressurization mechanism 72n selects a head pressurization state (see FIG. 5A) in which the thermal head 72a is pressed by the motor 72p and a head release state in which no pressurization is performed (see FIG. 5B). Can be taken. The thermal head 72a takes a print position when the pressurizing mechanism 72n is in the head pressurizing state, and takes a retracted position when the head is in the head released state. In order to efficiently transmit the torque of the motor 72p, the crank 72q reaches near the top dead center when the head is pressurized.

  In the head unit 72, when the paper P is transported between the thermal head 72a and the platen roller 72b in a state where the thermal head 72a is disposed at the printing position, the paper is used by the ink of the ribbon 72c heated by the thermal head 72a. A color image corresponding to magenta can be printed on P. When the paper P is transported between the thermal head 72a and the platen roller 72b, as the paper P is transported, the ribbon 72c is also moved from the ribbon supply roller 72d toward the ribbon take-up roller 72e. Sent.

  Similarly to the head portion 72, the other head portions 61, 71, 73 also have thermal head portions 61a, 71a, 73a, platen rollers 61b, 71b, 73b, ribbons 61c, 71c, 73c, ribbon supply rollers 61d, 71d, 73d and ribbon take-up rollers 61e, 71e, 73e, respectively. As will be described later, since the head holding shaft 73f of the thermal head 73a does not need to be moved in the conveyance orthogonal direction, the head holding drive mechanism 73k may not be provided on the head holding shaft 73f of the thermal head 73a. In this case, the number of members can be reduced.

  In the other head portions 61, 71, 73, instead of the tape-like ribbon 72c having an ink region to which ink corresponding to magenta of the head portion 72 is attached, inks corresponding to colorless and transparent, cyan, and yellow are attached respectively. Tape-shaped ribbons 61c, 71c, 73c having an ink area are used.

  As shown in FIG. 4, on the upstream side of the head unit 73 in the transport direction, on the downstream side of the head unit 72 in the transport direction, on the upstream side of the head unit 71 in the transport direction, and on the downstream side of the head unit 60 in the transport direction. A paper detection sensor 90 is provided as a detection unit that can detect the position of one end portion (right end portion in FIG. 4) in the direction orthogonal to the conveyance of the paper P during color image printing by each of the head portions 71 to 73. In FIG. 4, only the sheet detection sensor 90 on the upstream side in the transport direction from the head unit 73 and on the downstream side in the transport direction from the head unit 72 is illustrated.

  As shown in FIG. 6, the paper detection sensor 90 can advance and retreat with respect to the transport path of the paper P by a link mechanism 90 a that can move the paper detection sensor 90 in the transport orthogonal direction. Accordingly, the paper detection sensor 90 can selectively take a print position for detecting the position of one end portion in the conveyance orthogonal direction of the paper P and a retracted position for not detecting it. The paper detection sensor 90 takes a print position when the paper P is fed back upstream in the transport direction, and takes a retracted position when the paper P is transported downstream in the transport direction. This prevents the paper P from being conveyed downstream in the conveyance direction. The link mechanism 90a is supplied with power from another mechanism that interlocks with the transport operation of the paper P. Accordingly, it is not necessary to separately provide a motor, a gear mechanism, or the like in order to move the paper detection sensor 90 forward and backward with respect to the paper P conveyance path.

  As shown in FIG. 2, a pair of guide members 75 a to 75 c are disposed between the head unit 61 of the overcoat unit 60 and the head units 71 to 73 of the printing unit 70. Each of the pair of guide members 75a to 75c includes two plate-like members, and guides the sheet P (mainly the leading end portion of the sheet P) conveyed between the head portions 60 and 71 to 73, respectively. belongs to. Accordingly, the pair of guides 75a to 75c are arranged so as to face each other with a predetermined interval across the conveyance path of the paper P.

  The paper take-up unit 80 has a storage case 81 provided on the most downstream side of the transport path. The storage case 81 is formed in a substantially cylindrical shape, and a part of the storage case 81 is opened as an insertion opening 82 for the paper P. As shown in FIG. 2, in this embodiment, the central angle of the portion that becomes the insertion port 82 is about 90 degrees, and one edge 82 a is in the vicinity of the left end of the storage case 81, and the other edge The part 82 b is near the upper end of the storage case 81.

  The feeding roller pair 35 is disposed in the vicinity of the upper portion of the edge portion 82 a of the storage case 81, and the sheet P conveyed downward by the feeding roller 35 enters the storage case 81 from the vicinity of the end portion 82 a of the insertion port 82. Inserted. The paper P inserted into the paper winding unit 80 is guided by contacting the inner peripheral surface of the storage case 81. Therefore, in the storage case 81, the paper P is wound up in order from the leading end of the paper P so that the printing surface becomes the outer surface according to the curl of the paper P.

  The storage case 81 is rotatably provided with four winding rollers 83a to 83d. A part of each of the winding rollers 83 a to 83 d protrudes inward from the inner peripheral surface of the storage case 81. Therefore, since the frictional force when the paper P comes into contact with the inner peripheral surface of the storage case 81 is reduced, it is possible to suppress the paper P from being damaged.

  The discharge unit 95 discharges the paper P on which each color image printed by the cutting unit 50 is printed after the color image is printed in the printing unit 70 and the overcoat unit 60 is overcoated. It is. The discharge unit 95 includes a print box 96 that stores printed paper P. The print box 96 is a box-like member having an upper end opened, and is supported by a support shaft 97 at the lower end so as to be rotatable. Therefore, the print box 96 is stored in the housing 30a (shown by a solid line in FIG. 2), and the vicinity of the upper end portion is drawn from the front surface (right surface in FIG. 2) of the housing 30a (FIG. 2). And a state indicated by a broken line in FIG. Therefore, the operator can easily take out the paper P on which each color image is printed by pulling out the upper end portion of the print box 96 from the front of the printer 1 (housing 30a).

  An image detection sensor capable of detecting an end portion (mainly a rear end portion of the image) of the image printed on the paper P transported along the transport path on the upstream side of the cutting unit 50 in the transport direction. 91 is provided. A paper detection sensor 92 that can detect an end of the paper P in the transport direction is provided upstream of the overcoat unit 60 in the transport direction. In the present embodiment, the upstream end of the overcoat unit 60 in the conveyance direction and the detection position by the paper detection sensor 92 substantially coincide with each other.

  As shown in FIG. 3, the control device 20 includes a motor 43 a that drives the rotation shaft 43 of the paper supply unit 40, and a motor 31 a that drives the paper feed roller pair 31, the transport roller pair 34, and the feed roller pair 35. , 34a, 35a, an encoder 36 for detecting the rotation speed of the conveying roller pair 34, a drive mechanism 55 for driving the rolling cutter 51 of the cutting unit 50, and thermal heads 61a, 71a of the overcoat unit 60 and the printing unit 70. The head slide drive mechanisms 61k, 71k to 73k, the lift mechanisms 61l, 71l to 73l and the drivers 61q, 71q to 73q, the image detection sensor 91, the paper detection sensors 90 and 92, and the operation unit 10 are connected to the operation unit 10. Yes.

  The control device 20 includes hardware such as a CPU, a ROM, and a RAM controlled by appropriate software, and includes a maximum winding amount storage unit 21, a print information storage unit 22, a necessary winding amount calculation unit 23, and the like. The comparison unit 24, the winding amount determination unit 25, the conveyance amount detection unit 26, the conveyance control unit 27a, the print control unit 27b, and the cutting control unit 27c are included.

  When the paper P is transported from the paper supply unit 40 toward the paper winding unit 80, the maximum winding amount storage unit 21 sets the maximum length of the paper P that can be transported downstream of the printing unit 70 in the transport direction. Store as the maximum winding amount. The maximum winding amount depends on the length of the conveyance path between the printing position by the head unit 73 arranged on the most downstream side in the conveyance direction of the printing unit 70 and the insertion port 82 of the sheet winding unit 80, and the sheet winding unit. This is a value calculated by adding the length of the paper P that can be wound in the 80 storage cases 81. The maximum winding amount is input to the maximum winding amount storage unit 21 by the operator.

  The maximum winding amount largely varies depending on the size of the storage case 81. The length of the paper P that can be wound in the storage case 81 may be the maximum length of the paper P that can actually be stored in the storage case 81, or may be shorter than that. Can be set. Therefore, in the present embodiment, the length of the paper P that can be wound in the storage case 81 used when the maximum winding amount is calculated is that the paper P is damaged or scratched in the storage case 81. The length of the range not to be set is set to be shorter than the maximum length of the paper P that can be accommodated in the storage case 81.

  The print information storage unit 22 stores various setting values when a color image is printed. Settings include the print length of one frame for each print type (length in the transport direction), the number of prints (number of frames), the length of the margin formed between adjacent images, the additional length for head heat dissipation, etc. Is included. As the print length of one frame for each print type, a plurality of values are stored for each of a plurality of print types such as a standard size and a panorama size, for example. As the number of prints, a value input for each order by the operator before printing is stored. As the length of the margin between images and the additional length for heat radiation of the head, values input by the operator are stored before starting printing.

  The necessary winding amount calculation unit 23 calculates the length of the paper P necessary for printing all of the plurality of color images included in one order as the necessary winding amount. In other words, in order to print all of a plurality of color images included in one order, before starting printing of the color images in the printing unit 70, a sheet P having a length capable of printing these color images is set. It is necessary to transport the printing unit 70 downstream in the transport direction. Therefore, when the paper P is conveyed from the paper supply unit 40 toward the paper take-up unit 80, the print position by the head unit 73 of the printing unit 70 is set in order to print all of the plurality of color images included in one order. The length of the paper P that should be conveyed beyond the above is calculated as the required winding amount.

  Hereinafter, the necessary winding amount will be described with reference to FIG. FIG. 7 is a diagram illustrating a state in which a plurality of color images included in one order are printed in the vicinity of the leading end portion of the paper P. FIG. 7 illustrates a case where six images of the same print type are included in one order. As shown in FIG. 7, an area corresponding to the additional length z for heat radiation is provided in the vicinity of the leading end portion (left end portion in FIG. 7) of the paper P, and from there to the upstream side (right side in FIG. 7). Thus, an area corresponding to the print length x and an area corresponding to the margin length y are alternately provided by the number n of prints.

Therefore, when the operator inputs the print type and the number of prints of a color image included in one order before starting printing, the necessary winding amount calculation unit 23 sets each value stored in the print information storage unit 22 to each value. Based on this, the required winding amount L corresponding to one order is calculated by the following equation.
L = z + x * n + y * (n-1)

  As shown in FIG. 3, the comparison unit 24 compares the necessary winding amount calculated by the necessary winding amount calculation 23 with the maximum winding amount stored in the maximum winding amount storage unit 21, and the necessary winding amount. A comparison result is obtained for the magnitude relationship between the take-up amount and the maximum take-up amount.

  The winding amount determination unit 25 is actually conveyed downstream of the printing unit 70 in the conveyance direction before the conveyance direction of the paper P is changed from the direction toward the conveyance direction downstream side to the direction toward the conveyance direction upstream side. The length of the sheet P to be conveyed (actual winding amount), that is, the length of the sheet P actually conveyed beyond the position facing the head unit 73 of the printing unit 70 is determined. The winding amount determination unit 25 determines the winding amount based on the comparison result by the comparison unit 24. That is, when the comparison unit 24 obtains a comparison result that the required winding amount is equal to or less than the maximum winding amount, the winding amount determination unit 25 determines the actual winding amount as the necessary winding amount, and the comparison unit 24. When the comparison result that the necessary winding amount is larger than the maximum winding amount is obtained, the actual winding amount is determined as the maximum winding amount.

  The conveyance amount detection unit 26 detects the conveyance amount of the paper P based on the number of rotations of the conveyance roller pair 34 detected by the encoder 36 after the leading edge of the paper P is detected by the paper detection sensor 92. That is, the transport amount detection unit 26 detects the length of the paper P transported downstream in the transport direction from the detection position by the paper detection sensor 92. Therefore, the transport amount detection unit 26 is transported downstream of the printing unit 70 in the transport direction before the transport direction of the paper P is changed from the direction toward the downstream side in the transport direction to the direction toward the upstream side in the transport direction. The length of the paper P can be detected. After the leading edge of the paper P reaches the feed roller pair 35, the paper P is transported by the transport force of the feed roller pair 35, not the transport force of the transport roller pair 34. The transport amount detection unit 26 always detects the transport amount of the paper P based on the number of rotations of the transport roller pair 34.

  The transport amount detection unit 26 determines the transport amount of the paper P not only when the paper P is transported downstream in the transport direction but also when the paper P is transported upstream in the transport direction. Can be detected. Accordingly, when the transport direction of the paper P is changed from the direction toward the downstream side in the transport direction to the direction toward the upstream side in the transport direction, the transport direction is determined from the transport amount downstream in the transport direction before the transport direction is changed. The leading end position of the paper P can be detected by subtracting the transport amount upstream in the transport direction after the change.

  The conveyance control unit 27a controls the motors 43a, 31a, 34a, and 35a that drive the rotation shaft 43, the paper feed roller pair 31, the conveyance roller pair 34, and the feeding roller pair 35, respectively, thereby supplying the paper P to the paper supply unit. The paper P is transported from the paper winding unit 80 toward the paper winding unit 80, and the paper P is fed back from the paper winding unit 80 toward the paper supply unit 40. The printing control unit 27b controls the raising / lowering timing and printing timing of the thermal head 61 of the overcoat unit 60 and the thermal heads 71a to 73a of the printing unit 70, and the movement of the thermal heads 71a and 72a of the printing unit 70 in the conveyance orthogonal direction. . The cutting control unit 27 c controls the cutting timing at the cutting unit 50. The adjustment unit according to the present invention corresponds to the head slide drive mechanism 73k and the print control unit 27b.

  The operation of the printer 1 when printing an image will be described below with reference to the flowchart of FIG. 8 and FIG. FIG. 9 is a diagram illustrating a state of the head units 61 and 71 to 73 when printing an image of the printer.

  First, the leading end portion of the paper P, which is unwound when the rotary shaft 43 is rotationally driven from the winding portion 45 of the paper P loaded in the paper supply unit 40, mainly uses the conveying force of the paper feed roller pair 31. It is conveyed (step S101). Then, the conveyance by the paper feed roller pair 31 is continued until the leading end of the paper P passes through the conveyance roller pair 34 and reaches the paper detection sensor 92 (step S102). Here, when the leading edge of the paper P is detected by the paper detection sensor 92, a detection signal indicating that the leading edge of the paper P has been detected is transmitted from the paper detection sensor 92 to the control device 20. In this way, when the leading end of the paper P reaches the paper detection sensor 92, the conveyance of the paper P is stopped and the paper P enters a standby state (step S103). At this time, if the thermal heads 61a, 71a to 73a are at the print position, the thermal heads 61a, 71a to 73a are moved to the retracted position (step S104).

  Thereafter, when an order is received from the operator and the print type and the number of prints of the color image included in one order are input (step S105), the print information is prepared as preparation for starting the conveyance of the paper P. Based on the information stored in the storage unit 22, the necessary winding amount corresponding to the one order is calculated by the necessary winding amount calculation unit 23 (step S106). Then, the required winding amount is compared with the maximum winding amount stored in the maximum winding amount storage unit 21 by the comparison unit 24 (step S107). Based on the comparison result, the winding amount determination unit 25 determines the actual winding amount (step S108). In this way, after the preparation for transporting the paper P is completed, the paper P is transported mainly by the transport force by the transport roller pair 34 (step S109).

  Thereafter, the leading end portion of the sheet P passes through the overcoat unit 60 and the printing unit 70 in a state where the thermal heads 61 a and 71 a to 73 a are at the retracted positions. At this time, the overcoat and the image are not printed. Then, the conveyance mainly using the conveyance force by the conveyance roller pair 34 is continued until the pair of feeding rollers 35 is reached (step S110). Then, when the leading end portion of the paper P reaches the holding roller pair 35 and is sandwiched, thereafter, the paper P is transported mainly by the transporting force by the feeding roller pair 35, and the leading end portion of the paper P Are sequentially fed into the storage case 81 of the paper winding unit 80 (step S111). At this time, as the paper P is fed into the storage case 81, the leading end of the paper P is guided to the inner peripheral surface of the storage case 81 and the take-up rollers 83a to 83d. It is wound up according to the roll. Note that when the leading end of the paper P reaches the feed roller pair 35 and the main force of the transport force of the paper P is switched, the transport roller pair 34 starts feeding from the state where the transport force is applied to the paper P. The state is switched to a state in which the paper P is conveyed by the pair of intrusion rollers 35 and is rotated.

  Thereafter, when the paper P having the length of the winding amount determined by the winding amount determination unit 25 is transported to the downstream side in the transport direction from the printing position by the head unit 73, the winding of the paper P is finished. Thus, the conveyance of the sheet P from the sheet supply unit 40 toward the sheet take-up unit 80 is stopped (step S112). That is, the conveyance amount of the paper P detected by the conveyance amount detection unit 26 based on the number of rotations of the conveyance roller pair 34 detected by the encoder 36 after the leading edge of the paper P is detected by the paper detection sensor 92. When the winding amount determined by the winding amount determination unit 25 and the length of the conveyance path in the overcoat unit 60 and the printing unit 70 are equal to each other, the conveyance control unit 27a takes up the sheet P. And the conveyance of the paper P to the downstream side in the conveyance direction is stopped. At this time, the print position by the head unit 73 includes the rear end portion of the image printed on the most upstream side in the transport direction of the paper P having the winding amount.

  Then, the thermal head 61a of the overcoat unit 60, the thermal heads 71a to 73a of the printing unit 70, and the paper detection sensor 90 are simultaneously moved from the retracted position to the printing position (step S113). Thereafter, the paper P is fed back toward the upstream side in the transport direction with the transport force of the transport roller pair 34 as a main driving (step S114). Therefore, at this time, the conveyance roller pair 34 that is in the driven rotation state is rotationally driven in the direction of conveying the paper P toward the upstream side in the conveyance direction, and the feeding roller pair 35 is driven to rotate. Become. Further, the rotation shaft 43 of the paper supply unit 40 is rotationally driven in a direction in which the paper P is rewound into the magazine case 41.

  Then, while the paper P is fed back toward the upstream side in the transport direction, for each color image included in one order, printing corresponding to yellow is performed by the head unit 73, printing corresponding to magenta is performed by the head unit 72, and the head unit 71. Thus, printing corresponding to cyan is sequentially performed on the paper P so that they overlap. In this way, the printing of the color image (desired color image) is completed by performing printing on the paper P in the order of yellow, magenta, and cyan for each color image (step S115). Thereafter, the head unit 61 performs overcoating on the surface of the paper P on which the color image is printed (step S116).

  Further, during printing of a color image on the paper P by the head portions 71 to 73, the color of the color image is detected by the head portions 71 to 73 detected by the paper detection sensor 90 so that the color misregistration of each color is within an allowable range. Based on the position of one end of the paper P during printing in the direction orthogonal to the conveyance direction, the thermal head 73a of the head portion 73 (that is, the thermal head 73a on the most upstream side in the reverse feeding direction of the paper P among the three thermal heads 71a to 73a). ), The positions of the head holding shafts 71f, 72a of the thermal heads 71a, 72a of the head portions 71, 72 in the conveyance orthogonal direction are adjusted as needed. Specifically, the head holding shaft 71f of the thermal heads 71a and 72a is detected based on the position of one end portion in the conveyance orthogonal direction of the paper P during color image printing by the head portions 71 to 73 detected by the paper detection sensor 90. , 72f are respectively calculated as the movement distances of the positions in the conveyance orthogonal direction, and the positions of the head holding shafts 71f, 72f in the conveyance orthogonal direction are respectively moved by the calculated movement distances. In this way, the positions of the thermal heads 71a and 72a in the transport orthogonal direction are adjusted as needed with reference to the position of the thermal head 73a in the transport orthogonal direction (for example, a state indicated by a one-dot or two-dot chain line in FIG. 9) . In other words, the print start positions in the transport orthogonal direction of the thermal heads 71a and 72a are adjusted as needed with reference to the print start position (image formation start position) in the transport orthogonal direction of the thermal head 73a.

  In the present embodiment, a plurality of color images included in one order are printed intermittently so that a margin portion having a predetermined width is formed between the images. That is, as described above, on the paper P, an area corresponding to the additional length for heat insulation is provided in the vicinity of the leading end of the paper P, and then an image area and a blank portion are alternately provided. And in the printing part 70, when there exists an image area | region at the same timing in the position which opposes at least 2 among the three head parts 71-73, printing is simultaneously performed by those head parts. Further, the overcoat in the overcoat unit 60 is performed in parallel with the printing of the color image in the printing unit 70. In this way, in the printing unit 70 and the overcoat unit 60, a plurality of sheets P of the length of the winding amount determined by the winding amount determination unit 25 or the sheet P of the maximum winding amount length are provided. A color image is printed and overcoated.

  The rear end portion of the color image printed on the most upstream side in the transport direction (matches the rear end portion of the paper P having the length of the winding amount determined by the winding amount determination unit 25). When the cutting position is reached, the paper P is cut at the rear end of the color image (step S117). Note that the timing at which the trailing edge of the color image reaches the cutting position by the cutting unit 50 is detected based on the carry amount detected by the carry amount detection unit 26. After the sheet P is cut in this way, the sheet P (the length of the winding amount determined by the winding amount determination unit 25) on which the image upstream of the color image upstream of the conveyance direction is not formed is formed. The sheet P) on the upstream side in the transport direction from the rear end of the sheet P is rewound to the sheet supply unit 40.

  Then, when the paper P is continuously fed back and the rear end portion of the image upstream in the transport direction reaches the detection position by the image detection sensor 91, the rear end portion of the image from the image detection sensor 91 to the control device 20 A detection signal indicating that has been detected is transmitted (step S118). Then, after the trailing edge of the image is detected by the image detection sensor 91, the conveyance amount detection unit 26 determines that the leading end of the color image is a cutting unit based on the number of rotations of the conveyance roller pair 34 detected by the encoder 36. It is detected that the cutting position by 50 has been reached. At this time, the reverse feeding of the paper P is stopped, and the paper P is cut at the leading end of the color image (step S119).

  Thus, each time the paper P is cut at the leading edge of the color image, it is determined whether or not the color image printed on the cut paper P is the final image printed closest to the leading edge. Determination is made (step S120). Here, if it is determined that the image is not the final image, the paper P is reversely fed again. Then, after the paper P is cut at the leading end of the color image, the transport amount detecting unit 26 cuts the leading end in step S119 based on the number of rotations of the transport roller pair 34 detected by the encoder 36. It is detected that the trailing edge of the color image adjacent to the color image on the downstream side in the transport direction has reached the cutting position by the cutting unit 50. At this time, the reverse feeding of the paper P is stopped, and the paper P is cut at the rear end of the color image (step S121). Then, it returns to step S118 and the process similar to the above is repeated.

  On the other hand, if it is determined that the image is the final image, it is determined whether or not printing of all color images included in one order has been completed (step S122). Here, if it is determined that printing of all the color images included in one order has not been completed, the process returns to step S106 and the same processing as described above is repeated. On the other hand, when it is determined that printing of all the color images included in one order has been completed, the process ends.

  Note that when it is determined in step S122 that printing of all color images included in one order has not been completed, for example, the comparison unit 24 determines that the required winding amount is longer than the maximum winding amount. In this case, the winding amount determination unit 25 determines the maximum winding amount as the final winding amount. That is, in this case, among the color images included in one order, the remaining color images that could not be printed on the paper P having the maximum winding amount are continuously printed. In this way, the same processing as described above is repeated until printing of all color images included in one order is completed.

-Effect-
As described above, according to the present embodiment, the conveyance direction orthogonal to the sheet P detected by the sheet detection sensor 90 during formation of a desired color image on the sheet P by the head slide drive mechanism 73k and the print control unit 27b. Since the print start position in the conveyance orthogonal direction of the two thermal heads 71a and 72a among the three thermal heads 71a to 73a is adjusted as needed based on the position of the edge of the sheet P, the paper P during the formation of the desired color image is inclined. Even if the lines are lined up or the like, it is possible to suppress the shift of the print start position in the conveyance orthogonal direction with respect to the paper P of each thermal head 71a to 73a. Therefore, the occurrence of color misregistration for each color can be suppressed. Therefore, the quality of printed matter can be improved.

  Further, since a desired color image is formed on the paper P being conveyed, the quality of the printed matter of the color image can be improved.

  Further, based on the position of the end of the sheet P in the conveyance orthogonal direction detected by the sheet detection sensor 90 during the formation of a desired color image on the sheet P by the head slide drive mechanism 73k and the print control unit 27b, Of the three thermal heads 71a to 73a, the print start position in the transport orthogonal direction of the other thermal heads 71a and 72a is set as needed with reference to the print start position in the transport orthogonal direction of the most upstream thermal head 73a in the reverse feed direction. Since the adjustment is performed, it is not necessary to adjust the print start position in the conveyance orthogonal direction of all the thermal heads 71a to 73a. Therefore, compared with the case where the print start positions in the conveyance orthogonal direction of all the thermal heads 71a to 73a are adjusted, the adjustment of the print start positions in the conveyance orthogonal direction of the thermal heads 71a to 73a can be simplified.

(Other embodiments)
In the above embodiment, in the thermal sublimation printer 1, a color image is printed by the three head portions 71 to 73 that are in contact with the paper P. However, if the printer is capable of recording an image, the configuration of the head portion is used. Is not limited to this. For example, it may be a thermal printer (including a thermal transfer system and a thermal recording system) having a head in contact with the paper P, a FOCRT (Fiber Optic Cathode e-Ray-Tube), a leather light source, etc. A printer capable of recording a color image without contacting the paper P may be used.

  In the above embodiment, the printer 1 prints a color image on the paper P, but may print a monochrome image. In this case, a single head portion may be provided. At this time, even if the paper P on which a desired black-and-white image is being formed is skewed, it is possible to suppress the shift of the print start position in the direction perpendicular to the transport of the head to the paper P, thereby improving the quality of the printed matter. it can.

  Moreover, in the said embodiment, although three thermal heads 71a-73a are provided, you may provide two or four or more.

  In the above embodiment, two paper detection sensors 90 that can detect the position of one end of the paper P during the color image printing in the conveyance orthogonal direction are provided. However, one or three or more paper detection sensors 90 may be provided. .

  Further, in the above embodiment, on the upstream side of the head unit 73 in the transport direction, downstream of the head unit 72 in the transport direction, upstream of the head unit 71 in the transport direction, and downstream of the head unit 60 in the transport direction, Although the paper detection sensors 90 are provided, they may be provided anywhere as long as the position of one end in the direction perpendicular to the conveyance of the paper P during color image printing can be detected.

  In the above embodiment, printing in the transport orthogonal direction of the thermal head 73a is performed based on the position of one end in the transport orthogonal direction of the paper P detected by the paper detection sensor 90 during printing of the color image on the paper P. The print start position in the transport orthogonal direction of the thermal heads 71a and 72a is adjusted using the start position as a reference, but the print start position in the transport orthogonal direction of at least one of the thermal heads 71a to 73a may be adjusted. Also in this case, the occurrence of color misregistration of each color can be suppressed, so that the quality of the printed matter can be improved.

  It goes without saying that the present invention is not limited to the embodiments and can be applied to other embodiments that do not depart from the technical idea thereof.

  As described above, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  As described above, the present invention includes an image forming head for forming an image on a print paper being conveyed, and the image forming head forms a desired image by forming the image on the print paper. This is useful for an image forming apparatus that forms an image.

1 is a perspective view of a printer according to an embodiment of the present invention. It is a schematic block diagram of a printing part. It is a block diagram of various apparatuses of a control apparatus and a printer connected to this. It is a top view of a head part and a paper detection sensor. It is a side view of a thermal head and a raising / lowering mechanism. It is a top view of a paper detection sensor. It is a figure which shows a mode when the several color image contained in 1 order is printed in the front-end | tip part vicinity of a paper. FIG. 6 is a flowchart of an operation when printing an image of a printer. It is a figure which shows the mode of the head part in the case of printing the image of a printer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal printer 10 Operation part 20 Control apparatus 21 Maximum winding amount memory | storage part 22 Print information storage part 23 Required winding amount calculation part 24 Comparison part 25 Winding amount determination part 26 Conveyance amount detection part 27a Conveyance control part 27b Print control part (Adjustment part)
27c Cutting Control Unit 30 Printing Unit 34 Conveying Roller Pair 36 Encoder 38 Conveying Mechanism 40 Paper Supply Unit 50 Cutting Unit 60 Overcoat Unit 70 Printing Units 71a to 73a Thermal Head (Image Forming Head)
71k to 73k Head slide drive mechanism (adjustment unit)
80 Paper take-up unit 90 Paper detection sensor (detection unit)
95 Ejector P Printing paper (print paper)

Claims (4)

An image forming apparatus that includes an image forming head for forming an image on a print paper being conveyed, and forms a desired image by forming the image on the print paper by the image forming head. ,
A detection unit for detecting a position of an end of the paper transport orthogonal direction perpendicular to the paper transport direction in the print paper during formation of a desired image;
Based on the position of the end of the print paper in the paper transport orthogonal direction detected by the detection unit during formation of a desired image on the print paper, the image formation start position of the image forming head in the paper transport orthogonal direction is determined. An image forming apparatus, further comprising an adjustment unit for adjustment. The image forming apparatus according to claim 1.
The image forming heads are a plurality of image forming heads for forming images on printed paper being conveyed,
Each image forming head is configured to form a desired image by superimposing the images on the print paper.
The adjustment unit is configured to detect at least one of the plurality of image forming heads based on the position of the end of the print paper in the direction perpendicular to the paper conveyance direction, which is detected by the detection unit during formation of a desired image on the print paper. An image forming apparatus configured to adjust an image forming start position in a direction perpendicular to the paper conveyance of two image forming heads. The image forming apparatus according to claim 2.
Each of the image forming heads is arranged in order in the paper transport direction, and is for forming color images of different colors on the print paper being transported,
An image forming apparatus configured to form a desired color image by superimposing the color images on the print paper by the image forming heads. The image forming apparatus according to claim 3.
The adjustment unit is configured to detect the paper among the plurality of image forming heads based on the position of the end of the print paper in the direction perpendicular to the paper conveyance detected by the detection unit during formation of a desired color image on the print paper. It is configured to adjust the image formation start position of the other image forming heads in the paper conveyance orthogonal direction with reference to the image formation start position in the paper conveyance orthogonal direction of the most upstream image formation head in the conveyance direction. An image forming apparatus.

Images