JP2009131985A - Printing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing apparatus capable of using sheets of thermal paper with different paper widths while the amount of information to be printed is made equal. <P>SOLUTION: The printing apparatus is equipped with a thermal head 1 in which a plurality of thermal elements 145 are arranged in a line, a head holding mechanism 77 rotatably holding the thermal head 1, and a platen 71 with which the thermal head 1 held by the head holding mechanism 77 is brought into contact under a pressing condition. The head holding mechanism 77 holds one thermal head 1 among a plurality of the thermal heads 1 in which the thermal elements 145 are formed in different arranging pitches. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a printing apparatus that performs printing by selectively heating thermal paper that reacts with heat energy.

  A thermal printer is known as one of printing apparatuses. The thermal printer has a thermal head in which minute heating elements are linearly arranged. The micro heating elements arranged on the thermal head selectively generate heat when energized. The thermal energy selectively reacts with the color former contained in the thermal paper, thereby printing various information on the thermal paper. This printing method is called a thermosensitive coloring method. A thermal printer that prints by this thermal coloring method includes a thermal head and a platen on which the thermal head is pressed by a pressing structure, and selectively sandwiches the thermal paper between the thermal head and the platen. Transport while heating. At this time, printing is performed in response to the heat energy of the color former of the thermal paper. Thereafter, the printed thermal paper is nipped and conveyed by the thermal head and the platen, and is sent out of the thermal printer (see, for example, Patent Documents 1 and 2).

JP 2004-98699 A JP 2001-322304 A

  In the thermal printer described above, a predetermined number of minute heating elements are arranged on a thermal head at a constant pitch. For this reason, the maximum amount of information to be printed and the maximum print width are fixed. Accordingly, the paper width of the thermal paper used is determined. In recent years, there has been a movement to reduce the amount of thermal paper used for resource saving as much as possible. However, this type of thermal printer has a problem that it is difficult to use thermal paper having a narrow paper width while making the amount of information printed on the thermal paper equal.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A thermal head in which a plurality of heating elements are arranged in a line, a head holding mechanism that rotatably holds the thermal head, and the thermal head held by the head holding mechanism are in a pressed state. A printing apparatus comprising: a platen that abuts, wherein the head holding mechanism holds the thermal head of one of a plurality of types of the thermal heads in which the heating elements are formed at different arrangement pitches.

  Application Example 2 In the above-described printing apparatus, the plurality of types of thermal heads have the same number of heating elements formed in a row.

  According to these configurations, this printing apparatus holds any one of a plurality of types of thermal heads having the same number of heat generating elements formed at different arrangement pitches in the head holding mechanism, and is used as a heat sensitive recording medium. The paper can be nipped and conveyed by a thermal head and a platen for printing. Since the thermal head has the same number of heating elements formed at different arrangement pitches, print information composed of the same number of pixels can be printed with different widths. That is, it is possible to selectively use thermal paper having a plurality of paper widths with the same amount of information.

  Therefore, the information printed on the thermal paper having a wide paper width can be printed on the thermal paper having a narrow paper width without impairing the amount of information. Therefore, the amount of thermal paper used can be reduced. As a result, it is possible to reduce the cost of the roll paper to be used, contribute to the reduction of the running cost of the printing apparatus, reduce the amount of paper consumed, and save resources.

  In addition, since this printing apparatus prints information consisting of the same number of pixels, it can share print data consisting of the same number of pixels even when thermal heads having heating elements with different arrangement pitches are mounted. Furthermore, since the same number of heat generating elements are controlled, the control means can be shared.

  Application Example 3 The thermal head is provided with a support shaft serving as a fulcrum for rotation, and the head holding mechanism biases the support shaft of the thermal head and the thermal head toward the platen. The above-described printing apparatus, comprising a spring receiving portion having a spring and a groove portion for receiving the spring receiving portion.

  (Application Example 4) The above-described printing apparatus, wherein the thermal head is detachably held by the head holding mechanism.

  According to these configurations, the head holding mechanism of this printing apparatus inserts the support shaft of the thermal head and the spring receiving portion having the spring into the same groove, and the thermal head is biased by the spring to contact the platen or the like. By doing so, the thermal head can be held. Further, the thermal head can be removed by removing the bias of the spring. Therefore, it is possible to selectively hold a plurality of types of thermal heads having the same number of heating elements formed at different arrangement pitches in the printing apparatus.

  (Application example 5) A roll paper made of thermal paper having different paper widths is assumed for each of the plurality of types of thermal heads having the same number of the heating elements with different arrangement pitches, and a roll paper storage unit for storing the roll paper The roll paper storage part has a guide part for guiding a side surface of the roll paper, and the guide part is provided so as to be adjustable with respect to the paper widths of the plurality of types of roll papers. The printing apparatus as described above.

A plurality of types of thermal heads having the same number of heating elements formed at different arrangement pitches have a maximum printing width defined for each thermal head. A roll paper made of thermal paper having a predetermined paper width is set according to the maximum print width.
According to this configuration, the printing apparatus guides the roll paper having a paper width suitable for the thermal head being held by the guide portion whose side guide position is adjustable, and stably accommodates the roll paper in the roll paper accommodation portion. can do. Further, by guiding the side surface of the roll paper, stable paper feeding of the thermal paper can be ensured.

  (Application Example 6) The above-described printing apparatus, wherein the plurality of types of thermal heads include at least the thermal head in which the number of the heating elements is 512.

  According to this configuration, the printing apparatus can print information composed of 512 pixels. At this time, the plural types of thermal heads can share print data composed of 512 pixels. Furthermore, it is possible to share a control means for controlling 512 heat generating elements.

  (Application Example 7) The plurality of types of thermal heads include the thermal head in which the formation density of the heating elements is 180 dpi and the thermal head in which the formation density of the heating elements is 250 dpi. Printing device.

  According to this configuration, this printing apparatus prints information composed of 512 pixels at a pitch of 180 dpi, that is, about 0.141 mm, or 250 dpi, that is, about 0.101 mm pitch in the formation direction of the heating element of the thermal head. Can do.

  (Application Example 8) The roll corresponding to the thermal head in which the paper width of the roll paper corresponding to the thermal head in which the formation density of the heating elements is 180 dpi is about 80 mm and the formation density of the heating elements is 250 dpi The printing apparatus as described above, wherein the width of the paper is about 58 mm.

  According to this configuration, this printing apparatus can print 512 pieces of pixel information on thermal paper having a paper width of about 80 mm at a pitch of 180 dpi, ie, about 0.141 mm, and further, the same 512 pieces of pixel information can be printed at 250 dpi, ie, about It is possible to print on thermal paper having a paper width of about 58 mm at a pitch of 0.101 mm. Therefore, the amount of information to be printed can be made equal, and the paper width of the thermal paper used can be reduced from about 80 mm to about 58 mm. Therefore, the amount of thermal paper used can be reduced. As a result, it is possible to reduce the cost of the roll paper to be used, contribute to the reduction of the running cost of the printing apparatus, reduce the amount of paper consumed, and save resources.

  Hereinafter, the present embodiment will be described with reference to the drawings. In the drawings referred to in the following description, the vertical and horizontal scales of members or parts may be shown differently from the actual ones for convenience of description and illustration.

(Overall configuration of thermal printer)
A thermal printer as a printing apparatus according to the present embodiment will be described with reference to FIGS. FIG. 1 is a perspective view showing an external configuration of a thermal printer. 2 and 3 are perspective views showing the appearance of the printer mechanism, FIG. 2 is a perspective view of the printer mechanism with the cover frame open, and FIG. 3 shows the cover frame closed. It is a perspective view of a printer mechanism part.

  The thermal printer 100 is used in a POS system or the like, and is applied to printing and issuing a receipt, a coupon, or the like. The thermal printer 100 prints information on the thermal paper S using a roll-shaped thermal paper S (see FIG. 4). 1 to 3 indicates the width direction of the thermal paper S to be printed, the Y direction indicates the paper feed direction of the thermal paper S, and the Z direction is a direction orthogonal to the X direction and the Y direction. Indicates.

As shown in FIGS. 1 to 3, the thermal printer 100 includes an exterior case unit 200, a printer mechanism unit 300, and a control unit (not shown).
The printer mechanism unit 300 shown in FIGS. 2 and 3 is accommodated in the exterior case unit 200 shown in FIG. 1 together with a control unit made of a substrate or the like. Specifically, the printer mechanism unit 300 is fixed to the lower case 205 made of resin or the like, the side surface portion and the rear portion are covered with the upper case 210, and the front portion in the Y direction is covered with the panel 215. Yes. Further, the upper surface of the printer mechanism unit 300 is covered with an upper cover 220.

  As shown in FIG. 2, the printer mechanism unit 300 includes a paper cut unit 20 for cutting the printed thermal paper S and a roll paper storage unit 30 for storing and holding the roll-shaped thermal paper S. . The paper cutting unit 20 is arranged on the upper portion of the panel 215 shown in FIG. 1, and the paper cutting unit 20 is covered with a cutter cover 225. The cutter cover 225 can be pulled out by sliding in the direction of arrow A in FIG.

  As shown in FIG. 1, an open button 230 is provided on one side of the upper surface of the upper case 210 in the X direction. When the open button 230 is pushed down in the direction of arrow B in FIG. 1, the cover open lever 235 provided in the printer mechanism unit 300 can be rotated around the fulcrum 240. The cover open lever 235 is engaged with the lock mechanism of the cover frame 10 of the printer mechanism unit 300 shown in FIG. 2, and the lock mechanism is released by rotating clockwise. Further, the cover frame 10 is coupled to the upper cover 220.

  Therefore, when the open button 230 is pushed down in the direction of arrow B, the cover open lever 235 is rotated in the clockwise direction, the lock mechanism is removed, the upper cover 220 is opened in the direction of arrow C, and the roll paper storage unit 30 is exposed. That is, this state is a state in which the cover frame 10 of the printer mechanism unit shown in FIG. 2 is opened. By doing so, the roll-shaped thermal paper S can be set or taken out.

  Note that the thermal paper S used in the present embodiment has a printing surface composed of a coloring layer in which a color former is held by a binder or the like, and a roll-like thermal sensitivity formed by sequentially laminating this printing surface on the outer surface. Paper S. Hereinafter, the roll-shaped thermal paper S is also referred to as roll paper R (see FIG. 4). The thermal paper S, that is, the roll paper R is formed in a predetermined paper width. This paper width will be described later.

(About the printer mechanism)
Next, details of the printer mechanism will be described with reference to FIGS. FIG. 4 is a side cross section showing a side cross section of the printer mechanism. 5A and 5B are side views for explaining the mounting of the thermal head 1. FIG. 5A is a partial side view showing a state in which the thermal head is attached to the main body frame, and FIG. 5B shows a process of attaching the thermal head to the main body frame. It is a partial side view. The Y direction and the Z direction shown in FIGS. 4 and 5 are the same as the Y direction and the Z direction shown in FIGS.
As shown in FIGS. 2 to 4, the printer mechanism unit 300 includes a main body frame 60, a cover frame 10, a roll paper storage unit 30, a paper cut unit 20, and a printing unit 70.

  As shown in FIG. 2, the main body frame 60 is made of sheet metal or the like, and is formed in a substantially box shape having openings in the upper direction in the Z direction and the front in the Y direction. The cover frame 10 is provided on the upper rear side of the main body frame 60. The cover frame 10 is attached to be pivotable, that is, freely openable and closable around pivots 68 provided at upper ends on both sides of the rear part of the main body frame 60. The cover frame 10 is provided with an arcuate lid portion 15 for avoiding contact with the roll paper R when the cover frame 10 is closed. Further, when the installation angle of the printer is changed, that is, for example, when the printer is placed vertically, the lid portion 15 also functions as a holding member that receives the roll paper R.

  As shown in FIG. 2, the roll paper storage unit 30 is provided so as to be covered with the cover frame 10 at the rear side of the main body frame 60 formed in a box shape. The roll paper storage unit 30 includes a roll paper holder 31 and a pair of roll paper side guide plates 32.

  The roll paper holder 31 is formed of resin or the like, has a substantially arc-shaped depression corresponding to the maximum diameter of the roll paper R at the center, and a side opening of the arc-shaped depression at the bottom of the main body frame 60. It is attached so as to face both side surfaces of 60. The pair of roll paper side guide plates 32 are provided in the side direction of the roll paper holder 31 so as to be in contact with both side surfaces of the roll paper R to be accommodated with a slight gap. Therefore, the roll paper R is restricted in movement in the width direction by the pair of roll paper side guide plates 32 on the side surface, and is rotatably held in a substantially arc-shaped depression of the roll paper holder 31.

  The pair of roll paper side surface guide plates 32 are detachably provided from the roll paper holder 31. In the present embodiment, the roll paper side guide plate 32 is inserted and held in a groove provided in the paper holder 31. By selectively inserting the pair of roll paper side surface guide plates 32 into the grooves provided in the roll paper holder 31, roll paper R having different paper widths can be accommodated.

  Further, by removing the roll paper side guide plate 32 from the paper holder 31, the roll paper R having a larger paper width can be accommodated in the roll paper accommodating portion 30. At this time, both side portions on the inner side in the X direction of the main body frame 60 function as roll paper side surface guide portions. That is, the above-described roll paper accommodation unit 30 can accommodate a plurality of types of roll paper R having different paper widths.

  As shown in FIG. 3, the paper cutting unit 20 is provided in front of the main body frame 60, that is, at a position facing the support shaft 68 of the cover frame 10. The paper cutting unit 20 houses a movable blade 21 and its driving means. The movable blade 21 is rotated in the direction of arrow E about the fulcrum 22 by the driving means. As shown in FIG. 4, the movable blade 21 and the fixed blade 24 that intersects with the scissors are arranged on the cover frame 10 so as to face the paper cut portion 20.

  A gap between the fixed blade 24 and the movable blade 21 is connected to a paper outlet G through which the thermal paper S passes. For this reason, the thermal paper S is cut in the vicinity of the paper outlet G when the blade portion of the movable blade 21 rotated by the driving means and the blade portion of the fixed blade 24 cross each other in a scissors shape. A fixed blade cover 25 is provided above the fixed blade 24. When the thermal paper S is not cut, the movable blade 21 is accommodated in the paper cut portion 20 and the blade portion of the movable blade 21 is not exposed.

  As shown in FIG. 4, the printing unit 70 is provided on the paper cutting unit 20 side on the conveyance path D of the thermal paper S starting from the roll paper storage unit 30 and ending at the paper exit G of the paper cutting unit 20. Yes. As shown in FIGS. 4 and 5, the printing unit 70 includes a platen 71, the thermal head 1, and a head holding mechanism 77.

  The thermal head 1 is provided with head support shafts 102 on both side surfaces. Details of the thermal head 1 will be described later. The head holding mechanism 77 includes a notch 62 as a groove formed in the main body frame 60, a head pressing plate 72, and a spring 75 attached to the head pressing plate 72.

  As shown in FIG. 5B, the notch 62 has an opening above the main body frame 60, a groove 62a is formed on the platen side, and grooves 62b and 62c are formed above and below the position facing the groove 62a. Is formed. The thermal head 1 is attached to the main body frame 60 by inserting the head support shaft 102 into the notch 62 of the main body frame 60 and engaging the head support shaft 102 with the groove 62 a of the notch 62. The head pressing plate 72 is formed with bent portions 72b and 72c on the top and bottom, and a spring 75 which is a compression coil spring is fixed. The head pressing plate 72 is inserted into the notch 62, and the bent portions 72b and 72c engage with the grooves 62b and 62c of the notch 62, respectively.

  By doing so, the thermal head 1 and the head pressing plate 72 are supported on both sides of the notch 62 in a substantially parallel state. A spring 75 fixed to the head pressing plate 72 contacts the back surface of the thermal head 1. The thermal head 1 is biased toward the platen 71 by the spring 75.

  The above-described head holding mechanism 77 can be removed from the notch 62 by shifting the spring 75 fixed to the head pressing plate 72 from the back surface of the thermal head 1. The thermal head 1 can also be removed from the notch 62 when the biasing force from the spring 75 is lost. In this way, the thermal head 1 is detachably supported with respect to the main body frame 60.

  As shown in FIG. 2, the platen 71 is formed in a cylindrical roller shape by an elastic member such as rubber and is rotatably supported by the cover frame 10 via a platen bearing 73. A platen gear 74 is press-fitted into one shaft of the platen 71. The main body frame 60 is provided with a groove portion 64. When the cover frame 10 is closed, the platen 71 is guided to the guide slope portion 104 (see FIG. 4) of the thermal head 1, and then the platen bearing 73 is formed into the groove portion 64. Abut. Furthermore, a downward force acts on the cover frame 10 by the pressure applied to the platen 71 by the thermal head 1, and the position of the platen 71 is determined.

  5A, the platen 71 presses the thermal paper S in the direction of the thermal head 1 from the inner surface S2 side of the thermal paper S, and the thermal head 1 facing the platen 71 is The thermal paper S is pressed in the direction of the platen 71 from the outer surface S1 side of the thermal paper S to sandwich the thermal paper S. At this time, the color developing layer described above is formed on the outer surface S1 of the thermal paper S.

  As shown in FIG. 2, a paper feed motor 66 and a paper feed transmission gear 67 for rotating the platen 71 are provided on the side surface of the main body frame 60. As described above, when the platen 71 is positioned in the groove portion 64 of the main body frame 60, the platen gear 74 and the paper feed transmission gear 67 are engaged with each other, and the power from the paper feed motor 66 is transmitted to the platen 71.

  In the thermal printer 100 having the above-described structure, the cover frame 10 connected to the upper cover 220 is opened, the roll paper R made of the thermal paper S is set, the thermal paper S is pulled out to the paper outlet G, and is connected to the upper cover 220. By closing the cover frame 10, the thermal paper S is set between the platen 71 and the thermal head 1. Then, the paper feed motor 66 is started and the platen 71 is rotated to feed the thermal paper S, while selectively energizing the minute heating elements arranged in a straight line of the thermal head 1 to cause the minute heating elements to generate heat. The predetermined information can be printed on the thermal paper S.

  The printer mechanism unit 300 further includes a plurality of detection mechanisms. The detection mechanism will be described with reference to FIGS. 6A and 6B are diagrams illustrating the near-end detection mechanism, where FIG. 6A is a front view of the near-end detection mechanism, FIG. 6B is a cross-sectional view taken along line gg in FIG. It is gg sectional drawing of (a) which shows a state when it becomes a small diameter. The X direction, Y direction, and Z direction shown in FIG. 6 indicate the same directions as the X direction, Y direction, and Z direction shown in FIGS.

  As shown in FIG. 2, the paper detector 80 is provided on the printing unit 70 side of the roll paper holder 31. The paper detector 80 is a device that detects the presence or absence of the thermal paper S to be printed in the vicinity of the printing unit 70. The paper detector 80 is a reflective optical detector and detects the presence or absence of paper passing through the paper detector 80 portion. In addition, a hole 81 for dropping foreign matter and paper dust adhering to the thermal paper S downward is provided on the side of the paper detector 80 where the roll paper R is accommodated, that is, upstream in the paper feeding direction. Due to the influence, the paper detector 80 does not malfunction.

  As shown in FIG. 6, the near end detection mechanism 85 is provided on one side of the roll paper side guide plate 32 of the roll paper storage unit 30. The near-end detection mechanism 85 is an apparatus for detecting that the roll paper R has been consumed and the diameter is equal to or less than a predetermined diameter, that is, the remaining amount of the roll paper R has been reduced, and prompts the replacement of the roll paper R. is there.

  Hereinafter, the near-end detection mechanism 85 will be described by taking as an example the case where a roll paper R having a small paper width is stored. As shown in FIGS. 6A and 6B, the near-end detection mechanism 85 includes an actuator 87 and a microswitch 88 and is attached to the roll paper side surface guide plate 32. The actuator 87 is formed in a rectangular plate shape with resin or the like, and a substantially conical protrusion 89 is formed on one surface located at the end so as to protrude from the surface. In addition, two support shafts 86 are formed on the other upper surface of the actuator 87 so as to extend in parallel and outward at a certain distance from the surface.

The roll paper side surface guide plate 32 is provided with two support plates 92 on the surface opposite to the surface that guides the roll paper R so as to extend perpendicularly from the surface. The support plate 92 is formed with a U-shaped support portion 92a that opens upward in the Z direction. The support shaft 86 of the actuator 87 is attached to the support portion 92 a of the roll paper side surface guide plate 32, and is supported so as to be rotatable about the support shaft 86.
Further, a micro switch 88 is attached to the roll paper side guide plate 32 by a micro switch attachment plate (not shown). The micro switch 88 has a switch portion 88a, and is turned on and off when the surface 87a of the actuator 87 in the Z direction pushes the switch portion 88a when the actuator 87 rotates about the support shaft 86.

  As shown in FIG. 6B, when the large-diameter roll paper R is accommodated in the roll paper accommodation unit 30, the actuator 87 is such that the tip of the projection 89 of the actuator 87 hits the side surface of the roll paper R, It is stationary while rotating in the direction of arrow F (−) about the support shaft 86. When the roll paper R in the roll paper storage unit 30 is used and the diameter thereof is reduced, the roll paper R moves to the downward depression of the roll paper holder 31. The roll paper R has a paper tube 90 having a cavity at the center, and the thermal paper S is wound around the paper tube 90 in a roll shape.

  As shown in FIG. 6C, when the roll paper R having a small diameter moves to the recess of the roll paper holder 31, the tip of the projection 89 of the actuator 87 enters the cavity of the paper tube 90 of the roll paper R. As a result, the actuator 87 rotates about the support shaft 86 in the direction of the arrow F (+), and the surface 87a located on the opposite side of the support shaft 86 with respect to the projection 89 is the switch portion of the micro switch 88. Press 88a. Then, an on / off signal of the micro switch 88 is output, and it is detected that the roll paper R has been consumed and the diameter is equal to or smaller than a predetermined diameter, that is, that the remaining amount of the roll paper R has decreased.

  In this embodiment, the case where the roll paper R having a small paper width is accommodated in the roll paper accommodation unit 30 and the near end detection mechanism 85 is attached to the roll paper side guide plate 32 has been described as an example. However, for example, when a roll paper R having a large paper width is stored in the roll paper storage unit 30, that is, the roll paper side guide plate 32 is removed, and both side portions of the main body frame 60 function as the roll paper side guide unit. In this case, the near-end detection mechanism 85 may be provided on the side surface of the main body frame 60.

  As shown in FIG. 3, the above-described various detection mechanisms, the paper cutting unit 20, the lead wire group 13 of the paper feed motor 66, and the connection terminal of the thermal head 1 are relayed (not shown) fixed inside the right side surface of the main body frame 60. Connected to the board. Furthermore, a relay circuit board and a main circuit board (not shown) constituting a control unit for controlling the printer are connected by an FFC (flexible flat cable) 16 or the like. The main circuit board is provided at the bottom of the lower case 205 of the exterior case part 200.

(About thermal head)
Next, the thermal head 1 will be described with reference to FIGS. FIG. 7 is an external perspective view of the thermal head. FIG. 8 is a plan view of a head chip of a thermal head, where (a) is an overall view of the head chip, and (b) is a partially enlarged view of (a).

  As shown in FIG. 7, the thermal head 1 includes a heat radiating plate 106, a head chip 110, a head support shaft 102, and a connector 108. The heat sink 106 is a drawing material such as aluminum. The head chip 110 is attached to the locking surface 106b of the heat radiating plate 106 with a double-sided adhesive tape or the like. Since the width of the head chip 110 in the X direction is shorter than the width of the heat sink 106 in the X direction, a locking surface 106b that is a part of the heat sink 106 protrudes from the head chip 110 on the left and right sides of the head chip 110. It has become.

  In addition, a guide slope portion 104 is formed in the longitudinal direction of the heat sink 106 above the Z direction of the head chip 110 of the heat sink 106. When the cover frame 10 is closed, the guide slope portion 104 slides the platen 71 to guide it to a predetermined position. At this time, the inclination of the guide slope portion 104 has a predetermined angle so that the platen 71 does not collide with the head chip 110. In addition, the slope of the guide slope portion 104 is set to be approximately the same height as the head chip 110 attached in the vicinity of the guide slope portion 104. The head support shaft 102 is a cylindrical round pin, and is press-fitted into holes provided in the left and right side portions of the heat radiating plate 106.

Here, the head chip 110 will be described with reference to FIG. As shown in FIGS. 8A and 8B, the head chip 110 is a line for converting the energized current into heat along the longitudinal direction on the upper surface of the head substrate 112 made of alumina ceramic or the like having a long rectangular shape. The heating elements 140 are linearly arranged in a state protected by a protective film. A common wiring pattern 114 is disposed in a belt-like region between the heating element 140 and one side edge 112 a of the head substrate 112. Both ends of the common wiring pattern 114 are connected to the other side edge 112b of the head substrate 112.
The end is connected to the common terminal 116.

  As shown in FIG. 8B, a comb-like common electrode 114a is extended from the common wiring pattern 114. On the other hand, an individual electrode is formed so as to enter between the comb-like common electrodes 114a. One end of 118 is extended. The other end of each individual electrode 118 extends to the vicinity of the drive IC 120 mounted on the substrate, and a wire bonding pad 118a is formed at the end.

  The heating element 140 is formed so as to overlap the comb-like common electrode 114a and the individual electrode 118 that enters between them, as indicated by phantom lines in FIG. 8B. Therefore, the heating element 145 is defined by the adjacent comb-like common electrode 114a and the individual electrode 118. That is, when the selected individual electrode 118 is turned on, a current flows through the heating element 140 in a region surrounded by the individual electrode 118 and the comb-shaped common electrode 114a, and the portion functions as the heating element 145.

  That is, by selectively energizing the heating element 140 in each area, only the heating element 140 in the energized area instantaneously generates heat, and when the energization is stopped, the heat radiating plate 106 is quickly radiated. It is configured to be. Further, the heating element 140 is disposed in the vicinity of the contact point between the platen 71 that sandwiches and conveys the thermal paper S and the thermal head 1. Therefore, the heat energy generated from the heating element 140 is transmitted to the heating element 145 region of the thermal paper S.

  In addition, the driving IC 120 for driving and driving a predetermined number of heating elements 145 has a predetermined number of output pads 124 arranged in a staggered pattern on the upper surface of one side edge. The output pad 124 and the wire bonding pad 118a are connected by wire bonding. The drive IC 120 is sealed with an epoxy mold 130 shown in FIG. Further, a glass epoxy substrate 135 connected in the epoxy mold 130 is suspended from the other end. A connector 108 connected to the main circuit board (not shown) constituting the control unit for controlling the thermal printer 100 by the FFC 16 or the like is provided at the end of the glass epoxy board 135.

(Regarding the control method of the thermal head)
Next, a thermal head control method will be described with reference to FIGS. FIG. 9 is a control block diagram of the thermal head. FIG. 10 is a block diagram of the thermal head.

  As shown in FIG. 9, the control unit 400 of the thermal head 1 includes a CPU 420, a print buffer 430, a history buffer 435, a logic circuit 440, a selector 445, and a control circuit unit 450. The CPU 420 is connected to a host computer 500 that constitutes a POS system or the like. The host computer 500 sends control information such as print data and control data to the CPU 420. Then, the CPU 420 processes various input detection signals, various commands, various data, and the like according to the control program, and then outputs various control signals to the control circuit unit 450 and the like, thereby performing the printing operation of the thermal head 1. I have control.

  One dot line of the print pixel data sent from the CPU 420 is temporarily stored in the print buffer 430 and sent to the thermal head 1 via the selector 445. When printing pixel data for the next dot line is stored in the print buffer 430, the data in the print buffer 430 is moved to the history buffer 435 prior to this. The data stored in the history buffer 435 and the data stored in the print buffer 430 are calculated by the logic circuit 440 for each bit, that is, for each heating element 145, and output to the selector 445.

  The selector 445 is a kind of sequencer, and sequentially outputs data from the print buffer 430 and data from the logic circuit 440 in accordance with a data selector signal transmitted from the control circuit unit 450. That is, the energization period is divided into a part (period 1) corresponding to the data from the print buffer 430 and a part (period 2) corresponding to the data from the logic circuit 440. In the period 1, the data selector signal described above is divided. As a result, the data from the print buffer 430 and the data from the logic circuit 440 in the period 2 are respectively outputted to the thermal head 1.

  As shown in FIG. 10, the thermal head 1 includes a heating element 140 composed of a large number of heating elements 145 for simultaneously printing print pixel data of one dot line, and a plurality of heating elements 145 for heating and driving the heating elements 145 independently. Drive circuit 150, a shift register 155 and a latch register 160 for temporarily storing print pixel data of one dot line. The drive circuit 150 can be composed of a PNP transistor. By selectively driving the drive circuit 150, the corresponding heating element 145 is selectively heated, and the corresponding position on the thermal paper S is colored.

  The reason why the drive circuit 150 is expressed by a NAND circuit is to indicate a logical operation of the circuit. In other words, when the strobe signal is inactive (high level), the operation of the drive circuit 150 is prohibited. Such a circuit can be easily realized by connecting data and a strobe signal (positive logic) to the base of the PNP transistor in a wired OR circuit configuration.

The drive circuit 150 receives _four inverted signals (positive logic) of the strobe signals / St ₁ to / St ₄ generated by a delay circuit (not shown) and data (positive logic) output from the latch register 160, and receives both signals. It is driven according to the level. That is, when “1” data indicating “print” is given as the print pixel data, if the strobe signal is changed from “High” to “Low”, that is, effectively transitioned, the NAND circuit is configured. The drive circuit 150 outputs “Low”.

As a result, a potential difference from the head power supply voltage is generated in the corresponding heating element 145 and heated, and the corresponding area of the thermal paper S is colored by receiving this heat pulse. The strobe signal is supplied as three or four divided signals having different pulse widths. The four strobe signals / St ₁ to / St ₄ can be given by shifting their output timings by the delay circuit, thereby reducing the power supply voltage drop that occurs when a large number of drive circuits 150 are simultaneously energized. The problem can be avoided.

  Print pixel data for one dot line corresponding to the period is input to and held in the shift register 155 in synchronization with the clock signal. Note that the print pixel data is data corresponding to each print pixel for one dot line, but strictly speaking, the data indicating whether or not the heating element 145 of the print pixel 1 dot line is energized during the period. It is. The print pixel data is composed of a bit string of “1” meaning “energized” and “0” meaning “not energized”. Note that the shift register 155 is inputted with a predetermined calculation performed on the current print pixel data and the past print pixel data every predetermined energization period.

  The latch register 160 is connected in parallel to the shift register 155, and each bit data on the shift register 155 is transferred and held in the corresponding storage area simultaneously and in parallel. Accordingly, print pixel data corresponding to the next energization period can be input to the shift register 155 even during the energization period. The data transfer timing from the shift register 155 to the latch register 160 is controlled by the input timing of the latch signal L output from the control unit 400 to the latch register 160.

  This timing is after the previous energization period and before the next energization period, and after print pixel data corresponding to the next energization period is set in the shift register 155. As described above, each storage area of the latch register 160 is connected to one input terminal of the drive circuit 150. When new data is taken into the latch register 160 by the input of the latch signal L, according to the contents thereof. The input data to the drive circuit 150 changes immediately. Each drive circuit 150 energizes and drives the corresponding heating element 145 according to the data in the latch register 160 during the period when the delay strobe signal applied thereto is “Low” (active).

  In the control method of the thermal head 1 having the above-described configuration, the thermal paper S is transported while being sandwiched between the thermal head 1 and the platen 71 and is linearly arranged on the thermal head 1 based on the print pixel data. By selectively energizing the heat generating element 145 to generate heat, pixels of one dot line can be printed on the thermal paper S.

Example 1
Example 1 will be described with reference to FIGS. 11 and 13. FIG. 11 is a diagram for explaining the first embodiment, and FIG. 11A is a plan view of the thermal head used in the first embodiment as viewed from the surface on which the heating element is provided, and FIGS. ) Is a diagram showing a character pattern printed by the thermal head. FIG. 13 is a diagram showing print samples printed in Example 1 and Example 2. FIG. 13A is a diagram showing print samples printed in Example 1, and FIG. 13B is a diagram showing print samples printed in Example 2. FIG.

  As shown in FIG. 11A, on the head substrate 112a of the thermal head 1a mounted on the thermal printer 100 according to the first embodiment, the heating element 145a is 180 dpi (dots) along the longitudinal direction of the head substrate 112a. / Inch), in other words, 512 pieces are formed in a row at a pitch of about 0.141 mm. These 512 heating elements 145a constitute one dot line. In FIG. 11A, a black square represents a heating area of the heating element 145a. In FIG. 11A, only the heating element 145a is shown, and other configurations are omitted.

  The thermal printer 100 according to the first embodiment equipped with the thermal head 1a drives the paper feed motor 66 shown in FIG. 2 at a predetermined period to rotate the platen 71 at a constant speed, thereby causing the thermal paper S to generate heat from the thermal head 1a. It is set so that it can be fed at a paper feed pitch of approximately 0.141 mm, which is substantially equal to the density of the element 145a. As a result, as shown in FIG. 11 (b), a print area having a pitch of about 0.141 mm in both the dot line direction and the paper feed direction of the thermal head 1 a is formed on the thermal paper S. That is, by feeding paper while selectively energizing the heat generating element 145a to generate heat, pixels of about 0.141 mm wide × about 0.141 mm long can be freely formed on the thermal paper S.

  In the first embodiment, a case where character information is printed will be described as an example. As shown in FIG. 11B, for example, one character pattern is composed of 12 horizontal dots × 24 vertical dots. In the case of an alphabetic character, the maximum area is 12 dots wide by 24 dots long, and the upper and lower case letters are composed of 10 dots wide by 20 dots long. The maximum character size is 1.41 mm in the horizontal direction and 2 in the vertical direction. .82m. However, at this time, 2 dots in the horizontal direction (about 0.282 mm) are interdigit spaces, and uppercase letters are located at the top in the vertical direction of the character pattern consisting of 12 dots wide x 24 dots long, and 4 dots below. Space for minutes is provided. The lower case letters are located at the lower part in the vertical direction of the character pattern composed of horizontal 12 dots × vertical 24 dots, and a space for 4 dots is provided at the upper part.

  Since 512 heating elements 145a are formed in a row in the thermal head 1a, the maximum printing width of one dot line is about 72.2 mm (about 0.141 mm × 512). Further, when printing the above-described characters, the maximum number of print characters is 42 characters (512/12), that is, 42 digits.

  In Example 1, it is preferable to use roll paper R made of thermal paper Sa having a paper width of about 80 mm. Hereinafter, when the paper width of the thermal paper S is specified as about 80 mm, it is expressed as thermal paper Sa. The thermal paper Sa having a paper width of about 80 mm is the thermal paper S that is widely distributed in the market. In this case, as shown in FIG. 13A, character information having a maximum print area of 72.2 mm and a maximum number of print digits of 42 is printed in the approximate center of the thermal paper Sa having a paper width of about 80 mm.

  In this case, in the roll paper storage unit 30 of the printer mechanism unit 300 shown in FIG. 2, the roll paper side surface guide plates 32 are removed, and the inner sides of both sides of the main body frame 60 are used as side surface guides for the roll paper R having a paper width of about 80 mm. Use. At this time, the near end detection mechanism 85 is attached to the outside of the side surface of the main body frame 60.

  The thermal printer 100 according to the first exemplary embodiment has a maximum size of 512 dots and 42 digits of information with a character size of 1.41 mm in the horizontal direction and 2.82 m in the vertical direction on the heat-sensitive paper Sa having a width of about 80 mm. Can be printed. Therefore, it is possible to provide a printed matter such as a receipt or a coupon printed with a large character that is easy to see.

(Example 2)
A second embodiment will be described with reference to FIGS. 12 and 13. 12A and 12B are diagrams for explaining the second embodiment. FIG. 12A is a plan view of the thermal head used in the second embodiment as viewed from the surface on which the heating element is provided, and FIGS. ) Is a diagram showing a character pattern printed by the thermal head.

  The thermal printer 100 of the second embodiment includes the transmission gear 67 shown in FIG. 2 in the thermal head 1a in which the arrangement density of the heating elements 145b is 250 dpi, compared to the thermal printer 100 described in the first embodiment. The tooth wheel train is replaced with a tooth wheel train including a transmission gear capable of feeding the thermal paper S at a pitch of about 0.101 mm.

  As shown in FIG. 12A, a heating element 145b is placed on the head substrate 112b of the thermal head 1b mounted on the thermal printer 100 of the second embodiment along the longitudinal direction of the head substrate 112b at 250 dpi (dot / dot). Inch), in other words, 512 pieces are formed in a row at a pitch of about 0.101 mm. These 512 heating elements 145b constitute one dot line. In FIG. 12A, a black square represents a region of the heating element 145b. In FIG. 12A, only the heating element 145b is shown, and the other configurations are omitted.

  The thermal printer 100 of Example 2 having a gear train including a transmission gear capable of feeding the thermal paper S at a pitch of about 0.101 mm drives the paper feed motor 66 shown in FIG. By rotating at a constant speed, the thermal paper S can be fed at a paper feed pitch of about 0.101 mm, which is substantially equal to the density of the heating elements 145b of the thermal head 1b. As a result, a print area having a pitch of about 0.101 mm is formed on the thermal paper S in both the dot line direction and the paper feed direction of the thermal head 1b. That is, by feeding paper while selectively energizing the heating element 145b to generate heat, pixels of about 0.101 mm wide and about 0.101 mm long can be freely formed on the thermal paper S.

  In the second embodiment, a case where character information is printed will be described as an example. As shown in FIG. 12B, for example, one character pattern is composed of horizontal 12 dots × vertical 24 dots with respect to the maximum area of horizontal 12 dots × vertical 24 dots. In the case of English letters, both upper and lower case letters are composed of 10 dots wide x 20 dots long, and the maximum character size is about 1.01 mm in the horizontal direction and about 2.02 mm in the vertical direction. However, at this time, 2 dots (approximately 0.202 mm) in the horizontal direction are interdigit spaces, and uppercase letters are located at the top in the vertical direction of the character pattern consisting of 12 dots wide x 24 dots high and 4 dots below. Space is provided. The lower case letters are located at the lower part in the vertical direction of the character pattern composed of horizontal 12 dots × vertical 24 dots, and a space for 4 dots is provided at the upper part.

  Since 512 heating elements 145b are formed in a row in the thermal head 1b, the maximum printing width of one dot line is about 51.7 mm (about 0.101 mm × 512). Further, when printing the above-described characters, the maximum number of print characters is 42 characters (512/12), that is, 42 digits.

  In Example 2, it is preferable to use roll paper R made of thermal paper Sb having a paper width of about 58 mm. Hereinafter, when the paper width of the thermal paper S is specified as about 58 mm, it is expressed as thermal paper Sb. The thermal paper Sb having a paper width of about 58 mm is a thermal paper S that is widely distributed in the market, and the roll paper R made of the thermal paper Sb having a paper width of about 58 mm is easily available in the market. As shown in FIG. 13B, character information having a maximum printing area of 51.7 mm and a maximum number of printing digits of 42 is printed almost at the center of the thermal paper Sb having a paper width of about 58 mm.

  In this case, the roll paper storage unit 30 of the printer mechanism unit 300 shown in FIG. 2 has a roll paper side guide plate 32 attached, and the inside of both side surfaces of the roll paper side guide plate 32 is a roll paper R having a paper width of about 58 mm. Used as a side guide. At this time, the near end detection mechanism 85 is attached to the outer side surface of the roll paper side surface guide plate 32.

In the second embodiment, the replacement of the thermal head 1 and the transmission gear 67 and the attachment of the roll paper side surface guide plate 32 can be used for a general purpose without changing other components, print pixel data, and control method. On the thermal paper Sb having a paper width of about 58 mm, it is possible to print a maximum of 512 dots and 42 digits of information with characters having a character size of 1.01 mm (width) × 2.02 m (length). That is, the same amount of information as that printed on the thermal paper Sa having a paper width of about 80 mm can be printed on the thermal paper Sb having a paper width of about 58 mm while ensuring sufficient visibility.
Further, the vertical size of the characters can be reduced from 2.82 m in the vertical direction to 2.02 mm in the vertical direction in the first embodiment, and the total length of the thermal paper Sb having a paper width of about 58 mm to be printed with the same amount of information. Can be reduced.

  And by these things, the usage-amount of the thermal paper S used can be reduced to nearly half. Therefore, when printing the information amount of the same number of digits and the same number of lines, the consumption of the thermal paper S used can be greatly reduced while sufficiently ensuring the visibility, and the thermal printer of the second embodiment This can contribute to a reduction in running cost of 100 and can save paper resources.

(Example 3)
A third embodiment will be described with reference to FIG. 14A and 14B are diagrams for explaining the third embodiment. FIGS. 14A and 14B are diagrams showing character patterns printed by the thermal head used in the third embodiment.

  The thermal printer 100 according to the third embodiment is obtained by replacing the thermal head 1a with the thermal head 1b in which the arrangement density of the heating elements 145b is 250 dpi with respect to the thermal printer 100 described in the first embodiment. That is, using the thermal head 1b on which 512 heating elements 145b having a density of 250 dpi shown in FIG. 12A are formed, the thermal paper Sb having a paper width of about 58 mm is 180 dpi of the head density of the thermal head 1a, ie, about 0.141 mm. Paper is fed at a pitch.

  As a result, a print area having a pitch of about 0.101 mm in the dot line direction of the thermal head 1 b and a pitch of about 0.141 mm in the paper feed direction is formed on the thermal paper Sb having a paper width of about 58 mm. That is, by performing paper feeding while selectively energizing the heating element 145b to generate heat, pixels of about 0.101 mm wide and about 0.141 mm long can be freely formed on the thermal paper Sb having a paper width of about 58 mm. Can do.

  In the second embodiment, a case where character information is printed will be described as an example. As shown in FIG. 14A, for example, one character pattern is composed of a maximum of 12 horizontal dots × 24 vertical dots. For example, in the case of English characters, the upper and lower case letters are composed of horizontal 10 dots × vertical 20 dots with respect to the maximum area of 12 dots horizontal × 24 dots vertical. That is, 2 dots in the horizontal direction (about 0.202 mm) are interdigit spaces, and uppercase letters are located at the upper part of the character pattern pattern consisting of 12 dots wide x 24 dots long, and 4 dots below. Space is provided. Lowercase letters are located at the lower part in the vertical direction of the pattern of the character pattern composed of 12 horizontal dots × 24 vertical dots, and a space for 4 dots is provided at the upper part.

  As a result, a maximum character size of 1.01 mm (horizontal) × 2.82 m (vertical) can be realized. Since the thermal head 1b has 512 heating elements 145b formed in a row, the maximum print width is about 51.7 mm (about 0.101 mm × 512), and the maximum number of print characters is 42 digits (512 ÷ 12). It becomes. In Example 3, it is preferable to use roll paper R made of thermal paper Sb having a paper width of about 58 mm. Character information having a maximum printing area of 51.7 mm and a maximum printing digit number of 42 digits is printed on the thermal paper Sb having a paper width of about 58 mm.

  In the third embodiment, the character size is 1.01 mm (horizontal) on the thermal paper Sb having a paper width of about 58 mm without changing the other components by replacing the thermal head 1 and attaching the roll paper side guide plate 32. ) × 2.82 m (vertical) characters and printing with a maximum number of 42 digits is performed. Therefore, the paper width of the thermal paper S to be used can be reduced without reducing the amount of information to be printed, and the character height can be ensured as high as before. As a result, the width of the roll paper R used can be reduced, the character height can be kept high, and easy-to-read character information can be provided. Accordingly, the cost of the roll paper R can be reduced, and a printed matter such as a receipt or a coupon printed with a large character and easy to see can be provided.

Hereinafter, effects of the embodiment will be described.
(1) The thermal printer 100 described above can hold either the thermal head 1a or the thermal head 1b having different head densities via the head holding mechanism 77. Further, the roll paper storage unit 30 can store the roll paper R having a paper width of about 58 mm by attaching the roll paper side guide plate 32 to the roll paper holder 31 of the roll paper storage unit 30. By removing 32, roll paper R having a paper width of about 80 mm can be accommodated. Further, the paper feed pitch of the thermal paper S can be changed by exchanging the transmission gear 67 provided in the main body frame 60. That is, the thermal printer 1, the roll paper side guide plate 32, and the transmission gear 67 are replaced, and the other components are the same, and the thermal printer 100 corresponding to various specifications can be provided.

  (2) Both the thermal head 1a and the thermal head 1b mounted on the above-described thermal printer 100 have 512 heat generating elements 145a and heat generating elements 145b, that is, the same number. Therefore, the number of drive ICs 120 mounted on the thermal head 1 can be made equal. Moreover, the structure of the character pattern used can also be made common. Therefore, the circuit and control method of the thermal head 1 can be made common to the thermal printer 100 corresponding to various specifications. In other words, it is possible to provide the thermal printer 100 corresponding to various specifications without changing the circuit and the control method only by exchanging mechanical parts such as the thermal head 1, the roll paper side guide plate 32, and the transmission gear 67. it can.

  As mentioned above, although embodiment of this invention was described, various deformation | transformation can be added with respect to the said embodiment in the range which does not deviate from the meaning of this invention. For example, modifications other than the above embodiment are as follows.

  (Modification 1) In this embodiment, 512 thermal elements 145a are formed in a row at a density of 180 dpi (about 0.141 mm pitch) on the thermal head 1a and printed on thermal paper Sa having a paper width of about 80 mm. The case where the heating elements 145b are formed on the head 1b in a row with a density of 250 dpi (about 0.101 mm pitch) and printed on the thermal paper Sb having a paper width of about 58 mm has been described as an example, but the present invention is not limited thereto. Not. On one thermal head, 576 heating elements are formed in a row at a density of 203 dpi (about 0.125 mm pitch) and printed on thermal paper Sa having a paper width of about 80 mm, and the heating elements are placed on another thermal head at 280 dpi. May be formed in a row at a density of about 0.091 mm and printed on thermal paper Sb having a paper width of about 58 mm.

  In the first modification, a thermal head is replaced with another thermal head, the roll paper side guide plate 32 is attached to the roll paper holder 31, and a roll paper R having a width of about 58 mm is accommodated. The information composed of 576 pixels printed on the thermal paper Sa having a paper width of the same is printed on the thermal paper Sb having a paper width of about 58 mm by using another thermal head. be able to.

  Therefore, the amount of printed information is not reduced, and the paper width of the thermal paper S to be used can be reduced from about 80 mm to about 58 mm. That is, the paper consumption can be reduced by reducing the width of the roll paper R to be used. Accordingly, cost reduction of the roll paper R can be realized, and resource saving can be realized.

  (Modification 2) In the present embodiment, the printer mechanism unit 300 is described as an example of the so-called stand-alone type in which the exterior case unit 200 is accommodated, but the present invention is not limited to this. For example, the printer mechanism unit 300 may be in the form of being incorporated in a POS system or in the form of a multifunction machine that is integrally incorporated with other peripheral devices.

(Modification 3) In this embodiment, as a method of holding the thermal head 1, the case where the notch 62 is provided in the main body frame 60 and the thermal head 1 is held by the head pressing plate 72 and the spring 75 has been described as an example. However, it is not limited to this. As a holding method, a fastening part such as a screw may be used. It is sufficient that the thermal head 1 can be detachably held.
Moreover, although the case where the roll paper side surface guide plate 32 is inserted and attached to the groove portion of the roll paper holder 31 has been described as an example, the present invention is not limited thereto. As the attachment method, a fastening part such as a screw may be used. It is sufficient if the roll paper side guide plate 32 can be detachably attached.

The perspective view which shows the external appearance structure of a thermal printer. FIG. 3 is a perspective view of a printer mechanism unit with a cover frame opened. FIG. 3 is a perspective view of a printer mechanism unit with a cover frame closed. The side cross section which shows the side cross section of a printer mechanism part. The side view explaining attachment of a thermal head. The figure explaining a near end detection mechanism. The external appearance perspective view of a thermal head. The top view of the head chip of a thermal head. The control block diagram of a thermal head. The block diagram of a thermal head. FIG. 6 is a diagram illustrating Example 1; FIG. 6 is a diagram illustrating Example 2; The figure which shows the print sample printed in Example 1 and Example 2. FIG. FIG. 6 is a diagram illustrating Example 3;

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Thermal head, 20 ... Paper cut part, 30 ... Roll paper accommodating part, 32 ... Roll paper side guide plate, 60 ... Main body frame, 70 ... Printing part, 71 ... Platen, 85 ... Near end detection mechanism, DESCRIPTION OF SYMBOLS 100 ... Thermal printer, 110, 110a, 110b ... Head chip, 112, 112a, 112b ... Head substrate, 114a ... Common electrode, 118 ... Individual electrode, 120 ... Driving IC, 140 ... Heating element, 145 ... Heating element, 200 ... Outer case part, 205 ... Lower case, 300 ... Printer mechanism part, 400 ... Control part, 420 ... CPU, R ... Roll paper, S ... Thermal paper.

Claims (8)

A thermal head in which a plurality of heating elements are arranged in a row;
A head holding mechanism for rotatably holding the thermal head;
A platen with which the thermal head held by the head holding mechanism abuts in a pressed state;
The printing apparatus according to claim 1, wherein the head holding mechanism holds one of the plurality of types of thermal heads in which the heating elements are formed at different arrangement pitches.   The printing apparatus according to claim 1, wherein the plurality of types of thermal heads have the same number of heating elements formed in a row. The thermal head is provided with a support shaft serving as a fulcrum for rotation,
2. The head holding mechanism includes a groove portion that receives the support shaft of the thermal head, and a spring receiving portion having a spring that biases the thermal head toward the platen. Or the printing apparatus of 2.   The printing apparatus according to claim 1, wherein the thermal head is detachably held by the head holding mechanism. For each of the plurality of thermal heads having the same number of the heating elements with different arrangement pitches, roll paper made of thermal paper with different paper widths is assumed.
A roll paper storage unit for storing the roll paper;
The roll paper container has a guide part for guiding a side surface of the roll paper,
The printing apparatus according to claim 1, wherein the guide unit is provided so as to be adjustable with respect to a paper width of the plurality of types of roll paper.   6. The printing apparatus according to claim 1, wherein the plurality of types of thermal heads include at least the thermal head in which the number of the heat generating elements is 512. 6.   7. The thermal head according to claim 1, wherein the plurality of types of thermal heads include the thermal head in which the formation density of the heating elements is 180 dpi and the thermal head in which the formation density of the heating elements is 250 dpi. A printing apparatus according to claim 1.   The paper width of the roll paper corresponding to the thermal head having a heating element formation density of 180 dpi is about 80 mm, and the paper width of the roll paper corresponding to the thermal head having a heating element formation density of 250 dpi is about 80 mm. The printing apparatus according to claim 5, wherein the printing apparatus is 58 mm.

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