JP4324872B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus for forming an image on an image forming medium.

  As such an image forming apparatus, for example, a thermal printer disclosed in Patent Document 1 below is known. The printer includes a medium storage unit that stores a long thermal recording paper (corresponding to an image forming medium), and the thermal recording paper drawn from the medium storage unit is transported along a transport path. An image is formed by a color thermal head arranged along the path. The thermal recording paper on which the image has been formed is conveyed downstream as it is, cut by a frame by a cutter, and then discharged from the medium discharge unit to the outside of the apparatus.

  In the case of such an image forming apparatus, image formation can be performed only by transporting the thermal recording paper in one direction without reciprocating. However, since the thermal recording paper is drawn out and conveyed from the medium storage unit and the image is formed on the thermal recording paper at the same time, there is a possibility that the image quality is deteriorated due to a load variation during the conveyance of the thermal recording paper. In order to prevent image quality deterioration, an image is formed only after all three thermal heads of yellow, magenta, and cyan are brought into pressure contact with the thermal recording paper. Therefore, image formation is started only after the thermal recording paper is passed between the thermal head on the most upstream side and the thermal head on the most downstream side. Since image formation is performed by superimposing the images of each color in order from the upstream side, at the start of image formation, no image is formed on this spanned portion, which is wasted.

  On the other hand, a thermal printer disclosed in Patent Document 2 is known. This printer pulls out the thermal recording paper from the medium accommodating portion and once passes through the three thermal heads. Next, image formation is performed while the three thermal heads are in pressure contact and the thermal recording paper is fed back toward the medium accommodating portion. When a color image is formed by the three thermal heads, the thermal recording paper is conveyed again in the pull-out direction, cut into one frame size by a cutter, and then discharged from the medium discharge section to the outside of the apparatus.

  According to such a configuration, it is possible to suppress load fluctuations during conveyance of the thermal recording paper by pressing with the thermal head, and it is also possible to reduce the portion of the thermal recording paper that is wasted. However, since image formation and cutting with a cutter are performed for each frame, when image formation of a large number of frames is required, it is necessary to pull out and rewind the thermal recording paper. The number of times increases. As described above, when the number of times of switching in the transport direction is increased, the time required for the switching is wasted, and there is a problem that the processing efficiency of print creation is reduced.

  In order to deal with such a problem, the present applicant applied for an image forming apparatus having the following configuration in Japanese Patent Application No. 2004-80741 (prior art application). This image forming apparatus is provided on the front side of the apparatus, and temporarily accommodates a medium accommodating portion for accommodating a long image forming medium and an image forming medium provided on the rear side of the apparatus and pulled out from the medium accommodating portion. A medium take-up unit to be picked up and received; an image forming unit disposed in the middle of a conveyance path provided between the medium containing unit and the medium take-up unit; and a predetermined amount of image forming medium drawn out from the medium containing unit After being transported in the first direction along the transport path and taken up by the medium take-up unit, the image forming unit is fed back in the second direction opposite to the first direction, and the image forming unit The image forming apparatus includes a control unit that operates so as to perform formation, and a cutting unit that is disposed on the front side of the apparatus with respect to the image forming unit and cuts the image forming medium on which the image is formed in units of frames.

  According to this configuration, the image forming medium pulled out from the medium accommodating unit is conveyed in the first direction, passes through the image forming unit, and is then wound around the medium winding unit. After winding a predetermined amount of the image forming medium on the medium winding unit, image formation is performed by the image forming unit while being fed back in the second direction opposite to the first direction. The image forming medium on which image formation has been performed is cut into one frame units at the cutting unit and then discharged.

  According to such an image forming apparatus, if an image forming medium having a length corresponding to the required number of frames is previously wound on the medium winding unit, the necessary number of frames can be continuously obtained by pulling out the image forming medium therefrom. Images can be formed. Therefore, the number of reciprocating motions of the image forming medium can be reduced. In addition, since the image forming medium temporarily taken up by the medium take-up unit is pulled out and the image is formed, the problem of load fluctuation can be suppressed, and the image is formed before all the thermal heads are pressed. Can start. Therefore, a useless portion of the image forming medium does not occur as in Patent Document 2.

  Problems in the image forming apparatus will be described. After image formation on a long image forming medium, it is necessary to cut the image forming medium in units of one frame, but chips are generated during the cutting process. This chip is generated between the leading end portion of the image forming medium and between the frame images (see the margin W in FIG. 6). The chips are stored in a predetermined chip storage unit and disposed of at an appropriate timing. Therefore, it is necessary to facilitate the removal of chips.

  In the case of the configuration described in Patent Document 1 described above, the image forming medium is transported only in one direction, and a cutting unit can be disposed in the immediate vicinity of the medium discharging unit that performs print discharging. Accordingly, the chips can be easily taken out.

On the other hand, in the case of the prior application technique described above, it is necessary to transport the image forming medium from the medium accommodating section provided on the front side of the apparatus to the medium winding section provided on the back side of the apparatus. It is difficult to place it in the immediate vicinity. Therefore, the structure for making it easy to take out the chips accommodated in the chip accommodating portion is required.
Japanese Patent Application Laid-Open No. 8-174476 JP 2001-246769 A

  The present invention has been made in view of the above circumstances, and the problem is that an image with good image quality can be formed, the image forming process can be efficiently performed, and chip removal can be easily performed. An image forming apparatus is provided.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
A medium accommodating portion that is provided on the front side of the apparatus and accommodates an elongated image forming medium;
A medium take-up unit that is provided on the back side of the apparatus and temporarily takes up and stores the image forming medium drawn from the medium containing unit;
An image forming unit disposed in the middle of a conveyance path provided between the medium storage unit and the medium winding unit;
A predetermined amount of the image forming medium is pulled out from the medium accommodating portion, conveyed in the first direction along the conveying path, and wound on the medium winding portion, and then the image forming medium is second opposite to the first direction. A control unit that operates to cause the image forming unit to form an image while performing reverse feeding in the direction of
A cutting unit that is disposed on the front side of the apparatus with respect to the image forming unit and that cuts the image forming medium on which the image is formed in units of frames;
A chip container for storing chips generated by cutting the image forming medium;
A medium discharge section for discharging the cut image forming medium from the front side of the apparatus;
A transport surface opening and closing mechanism for exposing the transport surface of the transport path,
By this conveying surface opening / closing mechanism, the chip accommodating portion can be taken out with the conveying surface exposed.

  The operation and effect of the image forming apparatus having this configuration will be described. The long image forming medium is accommodated in the medium accommodating portion. The medium accommodating portion is provided on the front side of the apparatus. On the back side of the apparatus, there is provided a medium take-up unit that temporarily takes up and stores the long image forming medium drawn from the medium containing unit. An image forming unit for forming an image is disposed on the conveyance path between the medium storage unit and the medium winding unit.

  Prior to the image formation, a predetermined amount of the image forming medium is pulled out from the medium accommodating portion, conveyed along the conveying path, and taken up to the medium winding portion. The transport direction at this time is a direction from the front side of the apparatus toward the back side of the apparatus, and this is defined as a first direction. Although the image forming unit passes through the medium winding unit when it is wound, the image formation is not performed at this time. When the winding of the image forming medium to the medium winding unit is completed, the image forming medium is conveyed in the opposite direction (second direction). At this time, image formation by the image forming unit is performed. Since a predetermined amount of the image forming medium is temporarily wound around the medium winding unit, the image forming medium can be continuously formed while transporting the image forming medium in the second direction. A cutting unit is provided on the front side of the apparatus from the image forming unit, and cuts the image forming medium in units of frames. Chips generated during the cutting are accommodated in the chip accommodating portion.

  On the other hand, the function for taking out the chip accommodated in the chip accommodating part is provided. That is, a transport surface opening / closing mechanism for exposing the transport surface of the transport path is provided, and the transport surface is exposed by the transport surface opening / closing mechanism. In this state, the chip accommodating part can be taken out. As a result, it is possible to provide an image forming apparatus that can form an image with high image quality, can efficiently perform image forming processing, and can easily perform chip removal work.

  In the present invention, the transfer surface opening / closing mechanism has a rotation fulcrum on the back side of the apparatus and a locking portion on the front side of the apparatus, and a mechanism above the transfer surface around the rotation fulcrum is above the transfer surface. It is preferable to be configured so as to be moved.

  By providing the rotation fulcrum on the back side of the apparatus, the conveying surface can be exposed from the front side of the apparatus, and the chip accommodating portion can be easily taken out.

  In the present invention, it is preferable that a conveyance roller pair for conveying the cut image forming medium is provided in the vicinity of the chip accommodating portion, and the conveyance roller pair is also configured to move upward.

  A pair of conveyance rollers for conveying the image forming medium is also provided in the vicinity of the chip accommodating portion. If the mechanism is lifted upward while leaving a part of the conveying roller pair (one of the roller pair), this roller may be in the way, making it difficult to take out the chip storage portion. Therefore, if the conveying roller pair is lifted upward, the chip accommodating portion can be easily taken out.

  A preferred embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating an internal configuration of the image forming apparatus. This image forming apparatus includes a thermal sublimation type thermal printer (hereinafter simply referred to as “printer”).

  As shown in FIG. 1, the printer is provided with various mechanisms in a housing 1 having a substantially rectangular parallelepiped shape. The paper storage unit 2 (corresponding to a medium storage unit) stores a long paper (corresponding to an image forming medium) in the form of a roll. The paper take-up unit 3 (corresponding to the medium take-up unit) has a function of temporarily taking up the paper drawn out from the paper storage unit 2. A transport mechanism for transporting the paper along the transport path between the paper storage unit 2 and the paper take-up unit 3 is provided. The paper container 2 is disposed on the front side of the apparatus (the right side in FIG. 1). The paper take-up unit 3 is disposed on the back side of the apparatus (left side in FIG. 1).

  An image forming unit 4 is provided along the conveyance path between the paper storage unit 2 and the paper winding unit 3. The conveyance direction when the paper drawn out from the paper storage unit 2 is taken up by the paper take-up unit 3 is indicated by an arrow A in FIG. 1 and is defined as a first direction. The direction when the paper taken up by the paper take-up unit 3 is drawn out and conveyed from the paper take-up unit 3 is indicated by an arrow B in FIG. 1, and this is defined as the second direction. . Image formation by the image forming unit 4 is performed when the paper is conveyed in the second direction.

  The paper storage unit 2 is provided with a rotating shaft 2a that is rotationally driven by a motor, and the paper is stored around the rotating shaft 2a in a roll shape. When pulling out the paper from the paper container 2, the motor is driven to rotate the rotary shaft 2a counterclockwise. When winding the paper once drawn, the rotating shaft 2a is rotated clockwise.

  A feed roller pair 5 is provided in the vicinity of the paper storage unit 2, and the paper drawn by the feed roller pair 5 is changed in direction by the turn roller unit 6. Paper is conveyed toward the front side of the apparatus by the feed roller pair 5, but is conveyed toward the rear side (first direction) of the apparatus by the turn roller unit 6.

  A cutting portion 7 is disposed adjacent to the turn roller unit 6 and is configured to be similar to the fixed blade 7a and the movable blade 7b. The cutting unit 7 has a function of cutting the paper on which the image has been formed in units of one frame. The cut paper is discharged from a paper discharge unit 8 (corresponding to a medium discharge unit) provided on the front side of the apparatus. As shown in FIG. 3, the movable blade 7b is configured by a circular rolling cutter. Before and after the cutting unit 7 in the conveying direction, the pressure roller pairs 9 and 10 are arranged. When the cutting unit 7 cuts the paper, chips are generated. The chips are stored in a chip storage box 11 (corresponding to a chip storage unit).

  The movable blade 7b has a disk shape, and a blade is formed on the entire circumference of the movable blade 7b. And the center part of the movable blade 7b is hold | maintained with the axis | shaft. The movable blade 7b is connected to the drive mechanism via a shaft. The drive mechanism rotates and drives the movable blade 7b through this shaft, and moves forward or backward along the direction (paper width direction) perpendicular to the paper transport path (see FIG. 3). On the other hand, the fixed blade 7a is a rectangular blade that is disposed so as to be orthogonal to the paper transport path and is longer than the entire width of the paper transport path.

  Accordingly, in a state where the paper is arranged at the cutting position by the cutting unit 7, when the movable blade 7b is rotated and moved along the width direction of the paper, the paper is cut by the interaction between the movable blade 7b and the fixed blade 7a. Is done. As will be described later, in the printer of this embodiment, the cutting unit 7 cuts the paper at the leading end and the trailing end of each frame image.

  A pressing head 13 is provided in the middle of the conveyance path. When cutting the paper in the cutting unit 7, it is necessary to prevent the vibration during the cutting operation from being transmitted to the heads 40 to 43. Therefore, the press head 13 is used to loosen the paper in a predetermined direction. The slackening direction is above or below the transport surface, and may be any. The pressing head 12 has a function of preventing the paper fed out from the paper storage unit 2 from being bent by sandwiching the paper with a contact member (not shown).

  A main drive roller pair 14 is provided between the pressing head 13 and the image forming unit 4. The main drive roller pair 14 is connected to a drive motor (not shown), and transports the paper in the first direction or the second direction at a constant speed. An encoder 14a is connected to the main drive roller pair 14, and the rotation speed of the main drive roller pair 14 can be detected (see FIG. 4). This rotational speed corresponds to the amount of paper transport.

  The turn roller unit 15 has a function of storing paper in the paper winding unit 3 and a function of pulling out and transporting the paper wound and stored in the paper winding unit 3. By rotating the turn roller unit 15 counterclockwise by a motor, the paper can be temporarily accommodated in the form of being pushed into the paper take-up unit 3. A guide plate 15 a for guiding the paper to the paper take-up unit 3 and a guide mechanism 16 are provided. By rotating the turn roller unit 15 in the clockwise direction, the paper can be pulled out from the paper winding unit 3. Note that, unlike the paper container 2, the paper take-up unit 3 is not provided with a drive shaft or the like for rotationally driving the paper.

  The main drive roller pair 14 described above can take a state of being driven by a motor and a state of rotating by being driven by the paper conveyed by the turn roller unit 15 in order to convey the paper. The encoder 14a can detect the rotational speed in any state.

  When the paper is wound around the paper winding unit 3 by the turn roller unit 15, the paper is accommodated by contacting the inner peripheral surface of the guide mechanism 16. The guide mechanism 16 includes a belt conveyor that is driven in conjunction with the rotation of the pressure roller 15b of the turn roller unit 15, and is accommodated along the conveyor surface. Therefore, the paper can be wound and accommodated with a low frictional resistance. Thereby, it is possible to prevent the scratches on the paper surface. Moreover, in the paper winding part 3, it winds up in order from the front-end | tip of paper so that the image formation surface may turn into an outer surface according to the winding kite which paper has.

  The image forming unit 4 includes four heads, and includes a first head 40, a second head 41, a third head 42, and a fourth head 43 in order from the back side of the apparatus. The first head 40 forms an image corresponding to the yellow (Y) color, the second head 41 forms an image corresponding to the magenta (M) color, and the third head 42 changes to the cyan (C) color. A corresponding image is formed. A color image can be formed by sequentially superimposing these YMC three-color images. The fourth head 43 is overcoated on the paper surface after three color images are overlaid.

  The configuration of the first head 40 to the fourth head 43 will be described. Since all the heads have the same configuration, the first head 40 will be described as a representative. The first head 40 has a large number of heating elements (not shown) along the width direction of the paper, and a platen roller 40 a is disposed at a position facing the first head 40. Also, a tape-like ribbon 40b having an ink area to which ink corresponding to yellow is attached, a ribbon supply roller 40c around which the ribbon 40b before printing is wound, and a ribbon take-up roller that winds up the ribbon 40b after printing 40d.

  The first head 40 is configured to be close to and away from the paper transport path by a lifting mechanism (not shown). Therefore, the first head 40 can selectively take an image forming position where the ribbon 40b and the paper are pressed and a standby position where the ribbon 40b and the paper are not pressed between the vicinity of the tip and the platen roller 40a.

  When the first head 40 is transported between the first head 40 and the platen roller 40a in a state where the paper is transported in the second direction and the first head 40 is disposed at the image forming position. An image corresponding to yellow can be formed on the paper surface by the ink of the ribbon 40 b heated by the first head 40. At this time, when the paper is transported between the first head 40 and the platen roller 40a, the ribbon 40b also moves from the ribbon supply roller 40c toward the ribbon take-up roller 40d as the paper is transported. Sent.

  The other heads 41, 42 and 43 have the same configuration. In the second head 41, the third head 42, and the fourth head 43, ink corresponding to magenta, cyan, and colorless and transparent is attached in place of the tape-like ribbon 40b having an ink area to which ink corresponding to yellow is attached. A tape-shaped ribbon having an ink area is used.

  Note that a guide mechanism for guiding the paper is disposed in an appropriate place on the transport path. The guide mechanism is composed of, for example, a pair of plate-like members, and is configured such that paper passes between the pair of plate-like members.

  The paper discharge unit 8 is for discharging paper (finished print) that has been subjected to image formation and overcoating in the image forming unit 4 and cut in a frame unit in the cutting unit 7. The paper discharge unit 8 is provided with a print box (not shown) and stores the discharged paper.

  A distribution mechanism (not shown) is provided in the vicinity of the paper discharge unit 8. This sorting mechanism can switch the paper transport path between when the paper is wound around the paper storage unit 2 and when the paper on which the image is formed is discharged from the paper discharge unit 8. Therefore, by controlling this sorting mechanism, only the paper on which the image has been formed can be discharged from the paper discharge unit 8.

  Further, a sensor 17 capable of detecting an edge portion of an image formed on the paper conveyed along the conveyance path is provided in the direction of the front side of the cutting unit 7. On the other hand, a sensor 18 capable of detecting the end of the paper is provided on the apparatus front side of the fourth head 43.

  As already described, chips are stored in the chip storage box 11, but these chips need to be taken out and disposed of at an appropriate timing. As shown in FIG. 1, it is preferable that the chip storage box 11 is in the middle of the conveyance path so that it can be easily taken out. Therefore, a mechanism for easily taking out the chip storage box 11 is provided, and this point will be described below.

  The housing 1 can be divided into a fixed housing portion 1b and a movable housing portion 1c, and the movable housing portion 1c can be rotated around the rotation fulcrum 1a by a predetermined angle. A handle 1d is provided on the front side of the movable casing 1c. The fixed housing portion 1b and the movable housing portion 1c are locked to each other by a hook (not shown), but the movable housing portion 1c is rotated by a predetermined angle and lifted by releasing the hook and operating the handle 1d. be able to. The lifted state is shown in FIG.

  As shown in FIG. 2, the paper transport surface can be exposed by lifting the movable casing 1c. Thereby, the chip storage box 11 can be taken out easily. Further, both the fixed blade 7a and the movable blade 7b constituting the cutting portion 7 are lifted, and the entire pressure roller pair 9, 10 is also lifted. Therefore, when the chip storage box 11 is taken out, the fixed blade 7a and the roller are not disturbed, and the chip storage box 11 can be easily taken out. The main drive roller pair 14 is also lifted as a whole.

<Control block diagram>
Next, the control block configuration of the printer will be described with reference to FIG. The control device 20 (control unit) includes a motor 30 that drives the rotating shaft 2a of the paper storage unit 2, a motor 31 that drives the feed roller pair 5, a motor 31 that drives the main drive roller pair 14, and a turn roller unit 15. Motor 33 to be driven, encoder 14a for detecting the rotational speed of the main drive roller pair 24, drive mechanism 34 for the movable blade 7b of the cutting unit 7, lifting mechanisms 40e to 43e of the first to fourth heads 40 to 43, and a driver 40f To 43f, sensors 17, 18 and operation unit 19 are connected to each other.

  The control device 20 includes a CPU, ROM, RAM, and the like controlled by software. When the paper is transported from the paper storage unit 2 to the paper winding unit 3, the maximum winding amount storage unit 20 a sets the maximum paper length that can be transported downstream in the transport direction from the image forming unit 4. Remember as a quantity. This maximum winding amount is calculated by adding the length of the conveyance path between the first head 40 and the insertion port 3a of the paper winding unit 3 and the length of the paper that can be wound around the paper winding unit 3. It is a numerical value. This amount is entered by the operator.

  The print information storage unit 20b stores various setting values for forming a color image. Here, the set values include the print length of one frame for each print type (conveyance direction length), the number of prints (the number of frames), the length of the margin formed between adjacent images, and the head heat dissipation. The additional length can be raised. As the print length of one frame for each print type, for example, a plurality of values are stored for each of a plurality of print types such as a standard size and a panorama size. As the number of prints, a value input for each order by the operator before starting printing is stored. In addition, values set in advance at the stage of device configuration are stored as the length of the margin between images and the additional length for heat radiation of the head.

  The necessary winding amount calculation unit 20c calculates, as the necessary winding amount, the length of paper necessary to form all of the plurality of color images included in one order. That is, in order to form all of a plurality of color images included in one order, before forming a color image by the image forming unit 4, paper having a length capable of forming these color images is formed by the image forming unit 4. It is necessary to convey to the downstream side (paper winding unit side) in the conveyance direction. Accordingly, when the paper is transported from the paper storage unit 2 toward the paper take-up unit 3, the first head 40 of the image forming unit 4 is used to form all the color images included in one order. The length of the paper to be conveyed beyond the printing position is calculated as the necessary winding amount.

  The comparison unit 20d compares the required winding amount calculated by the required winding amount calculation unit 20c with the maximum winding amount stored in the maximum winding amount storage unit 20a. Then, the comparison unit 20d obtains a comparison result regarding the magnitude relationship between the necessary winding amount and the maximum winding amount.

  The winding amount determination unit 20e determines the winding amount based on the comparison result by the comparison unit 20d. That is, the winding amount determination unit 20e determines the actual winding amount as the necessary winding amount when the comparison unit 20d obtains a comparison result that the required winding amount is equal to or less than the maximum winding amount. On the other hand, when the comparison result that the required winding amount is longer than the maximum winding amount is obtained in the comparison unit 20c, the actual winding amount is determined as the maximum winding amount.

  The carry amount detector 20f detects the carry amount of the paper based on the number of rotations of the main drive roller pair 14 detected by the encoder 14a after the paper detection sensor 18 detects the leading edge of the paper. In other words, the transport amount detection unit 20f detects the length of the paper transported from the position detected by the sensor 18 toward the back side of the apparatus (first direction). Thereby, the length of the paper conveyed from the image forming unit 4 to the paper winding unit 3 can be detected. Here, after the leading edge of the paper reaches the turn roller unit 15, the paper is transported by the transport force by the turn roller unit 15 instead of the transport force by the main drive roller pair 14. The carry amount detection unit 20f always detects the carry amount of the paper based on the number of rotations of the main drive roller pair 14.

  The carry amount detection unit 20f can detect the carry amount not only when the paper is carried in the first direction but also when the paper is carried in the second direction. Therefore, when the transport direction of the paper is changed from the first direction to the second direction, the transport direction after the transport direction is changed from the transport amount in the first direction before the transport direction is changed. The leading edge position of the paper can be detected by subtracting the transport amount in the second direction.

  The conveyance control unit 20g controls the motors 30 to 33 to convey the paper in the first direction from the paper storage unit 2 toward the paper winding unit 3 and to convey the paper in the second direction. . The print control unit 20h controls the lifting timing and printing timing of the first to fourth heads 40 to 43. The cutting control unit 20 i controls the cutting timing at the cutting unit 7.

<Printing procedure>
Next, the operation when image formation is performed in the printer will be described with reference to the flowchart of FIG.

  First, the rotation shaft 2a in the paper storage unit 2 is rotationally driven, whereby the leading edge of the paper is pulled out by the conveying force of the feed roller pair 5 (# 01). The conveyance by the feed roller pair 5 is continued until the leading edge of the paper passes through the main drive roller pair 14 and reaches the sensor 18 (# 02). When the sensor 18 detects the leading edge of the paper, a signal to that effect is sent to the control device 20.

  When the leading edge of the paper reaches the position of the sensor 18, the paper conveyance is stopped and a standby state is entered (# 03). At this time, if the heads 40 to 43 are arranged at the printing position, the heads 40 to 43 are moved to the standby position (# 04).

  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 (# 05), the print information storage unit 20a prepares to start transporting the paper. Based on the stored information, the necessary winding amount corresponding to the one order is calculated by the necessary winding amount calculation unit 20c (# 06). The comparison unit 20d compares the necessary winding amount with the maximum winding amount stored in the maximum winding amount storage unit 20a (# 07). Based on the comparison result, the actual winding amount is determined by the winding amount determination unit 20e (# 08). After the preparation is completed, the paper is conveyed with the conveyance force by the main drive roller pair 14 as a main driving (# 09). At this time, the rotating shaft 2a and the feed roller pair 5 of the paper container 2 are both in a rotatable state.

  Thereafter, in a state where each of the heads 40 to 43 is disposed at the standby position, the conveying force by the main drive roller pair 14 is mainly driven until the leading end of the paper passes through the image forming unit 4 and reaches the turn roller unit 15. Is continued (# 10). When the leading edge of the paper reaches and is sandwiched by the turn roller unit 15, the paper is then transported mainly by the transport force of the turn roller unit 15, and from the leading edge of the paper into the paper winding unit 3. It is sent in sequentially (# 11). The paper is taken up in the paper take-up unit 3 according to the curl. Further, when the leading edge of the paper reaches the turn roller unit 15 and the main movement is switched, the main driving roller pair 14 is switched from a state in which a conveying force is applied to the paper to a state in which the paper is driven by the paper.

  Thereafter, when the paper having the length of the winding amount determined by the winding amount determination unit 20e is transported to the paper winding unit 3 side from the printing position by the first head 40, the winding of the paper is finished. Then, the conveyance of the paper in the first direction from the paper container 2 to the paper take-up unit 3 is stopped (# 12). That is, in the carry amount detection unit 20f, after the leading edge of the paper is detected by the sensor 18, the carry amount detected based on the number of rotations of the main drive roller pair 14 detected by the encoder 14a is the winding amount. When the amount of winding determined by the determination unit 20e and the length of the conveyance path in the image forming unit 4 coincide with the total length, the conveyance control unit 20g finishes winding the paper, The conveyance in the direction 1 is stopped. At this time, the end of the color image to be formed first is arranged at the image forming position by the first head 40.

  Next, the first to fourth heads 40 to 43 are moved from the standby position to the print position (# 13). Thereafter, the paper is conveyed in the second direction with the conveyance force of the main drive roller pair 14 as a main movement (# 14). Accordingly, at this time, the main drive roller pair 14 that has been driven to rotate is driven to rotate in the direction of transporting the paper toward the front side of the apparatus (second direction), and the turn roller unit 15 is driven to rotate. To come. Further, the rotation shaft 2 a of the paper storage unit 2 is rotationally driven in a direction in which the paper is rewound into the paper storage unit 2.

  Then, while the paper is transported in the second direction, for the color image included in one order, the first head 40 forms an image corresponding to yellow, the second head 41 forms an image corresponding to magenta, and the third Image formation corresponding to cyan is performed by the head 42. A color image is completed by superimposing the images of the respective colors in this order (# 15). Subsequently, overcoating is performed on the paper surface on which the color image is formed by the fourth head 43 (# 15). 16).

  Also, as shown in FIG. 6, image formation is continuously performed on a plurality of color images included in one order so that a margin W having a predetermined width is formed between the images. That is, as described above, after the region X corresponding to the additional length for heat radiation of the head is arranged in the vicinity of the leading end portion of the paper, the image G and the margin W are alternately arranged. In the image forming unit 4, when there are image areas at the same timing at positions facing at least two of the three heads 40, 41, 42, images are simultaneously formed by these heads. Further, the overcoat by the fourth head 43 is performed simultaneously with the formation of the color image.

  In FIG. 6, the images are formed in order from the right side (the front side of the apparatus) in the figure, but when the right end of the rightmost image reaches the cutting position by the cutting unit 7, the vicinity CU <b> 1 of the right end of the color image. Is disconnected (# 17). The timing at which the right end portion of the color image reaches the cutting position by the cutting unit 7 is detected based on the carry amount detected by the carry amount detection unit 20f. After the paper is cut in this way, the paper on the front side of the apparatus (right side in FIG. 6) rather than the first formed image (rightmost image in FIG. 6) is rewound into the paper storage unit 2. Is done.

  The paper continues to be conveyed in the second direction, and when the left end of the image on the front side of the apparatus (on the back side of the apparatus) reaches the detection position by the sensor 17, the sensor 17 moves the left end of the image to the control device 20. A signal indicating the detection is transmitted (# 18). The conveyance amount detection unit 20f detects the vicinity of the left end CU2 of the color image by the cutting unit 7 based on the number of rotations of the main drive roller pair 14 detected by the encoder 14a after the sensor 17 detects the left end of the image. Detecting that the cutting position has been reached. At this time, the conveyance of the paper in the second direction is stopped, and the paper is cut at the left end of the color image (# 19). Note that the positions CU1 and CU2 at which the paper is actually cut are set slightly inside the right end or the left end of the image. Thereby, it is possible to prevent the margin W from being included in the print.

  Whether the color image formed on the cut paper is the final image formed closest to the leading edge of the paper (leftmost in FIG. 6) each time the paper is cut at the left end of the color image Is determined (# 20). If it is determined that the image is not the final image, the paper is conveyed again in the second direction. Then, after the paper cutting at the left end of the color image is performed, the carry amount detection unit 20f performs the color cut in Step # 19 based on the number of rotations of the main drive roller pair 14 detected by the encoder 14a. It is detected that the right end of the next color image adjacent to the image has reached the cutting position by the cutting unit 7. At this time, the conveyance of the paper in the second direction is stopped, and the paper is cut at the right end of the color image (# 21). Then, it returns to step # 18 and repeats the same process.

  On the other hand, if it is determined that the image is the final image, it is determined whether or not all color images included in one order have been formed (# 22). Here, if it is determined that not all of the color images included in one order are formed, the process returns to step # 06 and the same processing is repeated. On the other hand, if it is determined that all color images included in one order have been formed, the process ends.

  Note that when it is determined in step # 22 that all the color images included in one order have not been formed, the required winding amount is longer than the maximum winding amount in the comparison unit 20d, for example. This is a case where the winding amount determination unit 20e determines the maximum winding amount as the final winding amount. That is, in this case, the remaining color images that could not be formed to the maximum winding amount among the color images included in one order are subsequently formed. In this way, the same processing as described above is repeated until all the formation of the color images included in one order is completed.

  As described above, the printer according to the present invention transports the paper in the direction from the paper storage unit 2 toward the paper winding unit 3 and then the main drive roller pair 14 disposed on the front side of the apparatus with respect to the image forming unit 4. A plurality of color images can be formed on the paper that is conveyed in the second direction by the conveying force of. Therefore, it is possible to form a color image from the front end portion of the paper conveyed in the second direction, and it is possible to suppress the deterioration of the image due to the load fluctuation during the paper conveyance. Further, even when a plurality of color images are formed on the paper, it is only necessary to reciprocate the paper once, and it is only necessary to switch the paper transport direction by the transport mechanism once. Can be reduced. Accordingly, it is possible to improve the processing capability of the printer while preventing deterioration in image quality due to paper waste and load fluctuation during paper conveyance.

  Further, since the paper is transported in the first direction in a state where all the heads 40 to 43 are arranged at the standby positions, the leading end of the paper is caught by the heads 40 to 43 and cannot be transported properly. It is possible to suppress the meandering of the paper when the heads 40 to 43 are in contact with each other (when a jam occurs).

  Further, since all of the heads 40 to 43 are simultaneously arranged at the print position immediately before the image formation is started, the other head moves from the standby position to the print position while the image formation is performed by one head. It is possible to prevent color misregistration from occurring due to load fluctuations caused by the vibration, paper vibration and elongation, and the like.

<Another embodiment>
In the present embodiment, in the thermal sublimation type printer, a color image is formed by the three heads 40 to 42 that are in contact with the paper that is the image forming medium. The configuration of the unit 4 is not limited to this. Therefore, it may be a thermal printer (including a thermal transfer system and a thermal recording system) having a head that comes into contact with the image forming medium, and includes, for example, an inkjet head, a FOCRT, a laser light source, and the like. It may be a printer capable of forming a color image without contact. The image forming unit does not necessarily have a plurality of heads, and may have only one head capable of forming a color image.

  In the present embodiment, the conveyance surface is inclined, but is not limited to this, and may be horizontal or curved in an arc shape. Moreover, although the conveyance surface is exposed by rotating the fixed housing portion, the conveyance surface may be exposed by sliding the fixed housing portion.

  The specific configuration of the transport surface opening / closing mechanism is not limited to that of the present embodiment. For example, a known mechanism can be adopted as the mechanism of the locking portion, and the mechanism is not limited to a specific structure. The location and shape of the chip storage box can be determined as appropriate.

Schematic diagram showing the configuration of a thermal printer (image forming device) The figure which shows the state which lifted the movable housing | casing part Diagram showing the configuration of the cutting part Control block diagram Flow chart showing print creation procedure Diagram showing the cutting position of paper

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 1a Rotation fulcrum 1b Fixed housing | casing part 1c Movable housing | casing part 1d Handle 2 Paper storage part 3 Paper winding part 4 Image formation part 5 Feed roller pair 7 Cutting part 7a Fixed blade 7b Movable blade 8 Paper discharge part 11 Cutting Waste storage box 14 Main drive roller pair 15 Turn roller unit 40 First head 41 Second head 42 Third head 43 Fourth head

Claims (3)

A medium accommodating portion that is provided on the front side of the apparatus and accommodates an elongated image forming medium;
A medium take-up unit that is provided on the back side of the apparatus and temporarily takes up and stores the image forming medium drawn from the medium containing unit;
An image forming unit disposed in the middle of a conveyance path provided between the medium storage unit and the medium winding unit;
A predetermined amount of the image forming medium is pulled out from the medium accommodating portion, conveyed in the first direction along the conveying path, and wound on the medium winding portion, and then the image forming medium is second opposite to the first direction. A control unit that operates to cause the image forming unit to form an image while performing reverse feeding in the direction of
A cutting unit that is disposed on the front side of the apparatus with respect to the image forming unit and that cuts the image forming medium on which the image is formed in units of frames;
A chip container for storing chips generated by cutting the image forming medium;
A medium discharge section for discharging the cut image forming medium from the front side of the apparatus;
A transport surface opening and closing mechanism for exposing the transport surface of the transport path,
An image forming apparatus characterized in that the chip accommodating portion can be taken out with the conveying surface opening / closing mechanism exposed.   The transport surface opening / closing mechanism has a rotation fulcrum on the back side of the apparatus and a locking portion on the front side of the apparatus, and moves a mechanism above the transport surface around the rotation fulcrum to move above the transport surface. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured as follows.   The image forming apparatus according to claim 2, wherein a pair of conveyance rollers for conveying the cut image forming medium is provided in the vicinity of the chip accommodating portion, and both the conveyance roller pairs are also moved upward. apparatus.

Images