1. This is a Divisional Application of prior U.S. patent application Ser. No. 09/230,568, which in turn is the National Phase Application of PCT/JP98/02311, having an International filing date of May 27, 1998.

FIELD OF THE INVENTION 2. The present invention relates to a printing apparatus for printing characters or figures on rolled paper by using a printer head, and, more particularly, to a printing apparatus having a considerably simple structure, with which replacement of the rolled paper and removal of jammed paper can be carried out easily, while decreasing paper jam incidents.

BACKGROUND OF THE INVENTION 3. In general, most of known printing apparatus of this kind have been such that the printed output is of a definite format, and, upon completion of printing, it generally sends out the printed output with a paper transfer mechanism such that a perforated line of recording paper comes out of the apparatus, allowing the printed output to be cut along the perforated line. 4. Accordingly, some apparatus have been proposed in recent years in which the printed output is transferred to a discharge port by using a transfer means, etc. after it is cut and while the printing is stopped for a moment within the apparatus, as shown in FIG. 26, in order to adapt to printed output of an irregular shape (varied in length) and to avoid paper jams due to consequent strain of the recording paper during the printing. That is, a numeral 51 in the figure represents rolled paper which is arranged so that it is cut in a predetermined length by a cutter unit 53 and transferred to a discharge port 55 by a presenter 54 after it is printed by a printer unit 52. Also, numeral 56 represents a rolled paper holder for rotatably supporting the rolled paper 51, and numerals 57 and 58 are a roller and a printer head, respectively, representing structural elements of the printer unit 52. 5. With the above described structure of the prior art, a leading end of the rolled paper 51 held in the rolled-paper holder 56 needs to be inserted into a feeding port (not shown in the figure) of the printer unit 52 when the rolled paper 51 is reset in the printer unit 52 for replacement of the rolled paper 51, or after removal of jammed paper, etc. In doing this task, however, the leading edge of the rolled paper 51 held in the rolled paper holder 56 can not be simply and easily inserted into the feeding port of the printer unit 52, and jammed paper between the rolled paper 51 and the printer unit 52 can not be readily removed, because of a very tight space between the rolled paper 51 and the printer unit 52 in the prior art structure. 6. There has been a fear that the rolled paper 51 is inadvertently rumpled or torn if the rolled paper 51 could not be easily set in position. Also, there has been another fear that a part of the jammed paper may be left behind in the printing apparatus if the jammed paper can not be removed easily. They have been causes leading to other paper jams. Widening the space between the rolled paper 51 and the printer unit 52 could resolve this problem, but it would raise a new problem in that the dimensional reduction of the apparatus is restricted. 7. Also, the structure of the prior art has frequently caused paper jams in the transfer presenter 54. Although there is a way to prevent it, in that the transfer presenter 54 is disused, and recording papers are freely dropped under their own weight to lead them to the discharge opening after printing, this poses a problem with papers that fly out of the discharge opening by impetus of the dropping. 8. Furthermore, the structure of the prior art tends to cause the rolled paper 51 to stick to a surface of the roller 57 or the printer head 58 during a long stand-by time, or if it is used in an environment of high temperature, high humidity, low temperature, low humidity, etc. regardless of the stand-by period, so as to result in a failure of feeding the paper in the succeeding printing operation and to become liable to cause a paper jam. Also, there have been cases in which the paper transferring operation is impaired due to oxidation, corrosion, hardening of grease, etc. of components such as a gear, an axle, a bearing, etc. that constitute a paper transfer mechanism. There have also been impairments with the operation of a cutter mechanism having a similar component structure. 9. The present invention is intended to solve the above problems, and it aims at providing a printing apparatus of a small size that facilitates the replacement of rolled paper, removal of jammed papers, etc. with a considerably simple structure. 10. The invention also aims at providing a printing apparatus of considerably simple structure that reliably delivers a printed output to a discharge port without causing a paper jam, even for printed output of an irregular shape (varied in length). 11. The invention further aims at providing a highly reliable printing apparatus which prevents a paper jam in a succeeding printing operation, and avoids impairment of the operation of the paper transfer mechanism and the cutter mechanism, even under such severe conditions as an extended stand-by time and a use environment of high temperature, high humidity, low temperature, low humidity, etc.

SUMMARY OF THE INVENTION 12. A printing apparatus of the present invention comprises a rolled-paper holder for supporting a rolled paper which is provided with a first holder for use in carrying out printing on the rolled paper and a second holder for use in setting the rolled paper. The rolled paper is moved from the second holder to the first holder on the rolled-paper holder as a main body of the apparatus is shifted from a position for carrying out setting work (paper setting position) to a position for the printing operation (printing work position). The above structure provides the apparatus with the effect of facilitating the setting of rolled paper and removal of jammed papers, and prevents paper jam, since it is provided with a holder for temporarily holding the rolled paper when the rolled paper is reset or when the rolled paper is provisionally evacuated for replacement of the rolled paper or removal of jammed papers, etc. 13. Also, the printing apparatus of the present invention comprises a printer unit for printing on the rolled paper, a cutter unit for cutting the rolled paper according to a printed length on the rolled paper, and an L-shaped guide unit for leading the cut paper toward a discharge port by letting the paper fall under its own weight. The discharge port is provided with a stopper for preventing the cut paper from flying out and a projection on a ceiling portion deep in the discharge port. This enables the structure to avoid use of a presenter and to prevent paper jams, because the effect of the stopper and the projection can positively prevent the cut paper from flying out, even when the printed output is of an irregular shape (varied in length). 14. Moreover, the printing apparatus of the present invention is designed to move the recording paper in a reverse direction after it is once moved in a forward direction, and to drive the cutter, when a predetermined amount of time has elapsed during a stand-by period. This effectively avoids the recording paper from being stuck completely with the roller or the printer head by temporarily freeing the paper which begins to stick, and, at the same time, prevents component parts of the paper transfer mechanism and the cutter mechanism from undergoing oxidation, corrosion, hardening of grease, etc., so as to avoid a paper jam.

BRIEF DESCRIPTION OF THE DRAWINGS 15. FIG. 1 is a structural drawing depicting a brief construction of a printing apparatus of a first exemplary embodiment of the present invention in open position for setting work; 16. FIG. 2 is a structural drawing depicting a construction of the same exemplary embodiment in closed position for normal printing operation; 17. FIG. 3A and FIG. 3B are structural drawings depicting a construction of the same exemplary embodiment in an intermediate position; 18. FIG. 4 is a structural drawing depicting a construction of a printing apparatus of a second exemplary embodiment of the present invention; 19. FIG. 5 is a structural drawing depicting a construction of a printing apparatus of a third exemplary embodiment of the present invention in a position for setting work; 20. FIG. 6 is a structural drawing depicting a construction of a printing apparatus of a fourth exemplary embodiment of the present invention; 21. FIG. 7 is a structural drawing depicting a main body of the apparatus of the same exemplary embodiment in an open position; 22. FIG. 8 is a partially sectioned front view of the main body of the apparatus of the same exemplary embodiment. 23. FIG. 9A to FIG. 9C are structural drawings depicting a construction of a discharge port of the same exemplary embodiment; 24. FIG. 10 is a structural drawing depicting a construction of a printing apparatus of a fifth exemplary embodiment of the present invention; 25. FIG. 11 is a side view of the same exemplary embodiment; 26. FIG. 12 is a front view of the same exemplary embodiment; 27. FIG. 13A and FIG. 13B are enlarged side views depicting a cutter unit of the same exemplary embodiment; 28. FIG. 14 is an enlarged front view depicting the cutter unit of the same exemplary embodiment; 29. FIG. 15 is a perspective view of a guide unit of the same exemplary embodiment; 30. FIG. 16 is a fragmentary perspective view of a discharge port and its vicinity in a printing apparatus of a sixth exemplary embodiment of the present invention; 31. FIG. 17A to FIG. 17D depict an operational flow of a printing apparatus of a seventh exemplary embodiment of the present invention; 32. FIG. 18A to FIG. 18D depict an operational flow of a printing apparatus of an eighth exemplary embodiment of the present invention; 33. FIG. 19A to FIG. 19E depict an operational flow of a printing apparatus of a ninth exemplary embodiment of the present invention; 34. FIG. 20A to FIG. 20E depict an operational flow of a printing apparatus of a tenth exemplary embodiment of the present invention; 35. FIG. 21A and FIG. 21B depict an operational flow of a printing apparatus of an eleventh exemplary embodiment of the present invention; 36. FIG. 22 is a perspective view depicting a construction of a printing apparatus of a twelfth exemplary embodiment of the present invention; 37. FIG. 23 is an operational flowchart during a stand-by period in the twelfth exemplary embodiment of the present invention; 38. FIG. 24 is an operational flowchart during a stand-by period in a thirteenth exemplary embodiment of the present invention; 39. FIG. 25 is an operational flowchart during a stand-by period in a fourteenth exemplary embodiment of the present invention; and 40. FIG. 26 is a structural drawing depicting a printing apparatus of the prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 41. The present invention is described in more detail according to the accompanying drawings.

First exemplary embodiment 42. FIG. 1 to FIG. 3B depict a brief structure of a printing apparatus of a first exemplary embodiment of the present invention, where FIG. 1 shows a main body of the apparatus in its open position, FIG. 2 shows the same in its closed position, and FIG. 3A to FIG. 3B show an intermediate position of the same. 43. In the figures, a numeral 1 represents rolled paper which is axially supported by a roller shaft 9 as well as a rolled-paper holder 2 provided on a back surface of the main body of the apparatus, and it is discharged via a cutter unit 4 after having been printed with a printer unit 3. Also, recording paper 1a cut by the cutter unit 4 in a predetermined length falls toward a discharge port 6 through a guide unit 5 having the shape of a duct. 44. The rolled-paper holder 2 is provided with a first holder 2b for securely supporting the rolled paper 1 while carrying out printing on the rolled paper 1 and a second holder 2a for temporarily supporting the rolled paper 1 when the rolled paper 1 is replaced or jammed paper is removed. The rolled paper 1 is rotationally or slidingly moved from the second holder 2a to the first holder 2b by a rolled-paper thruster 7, provided on a part of a housing for storing the main body of the apparatus, along with a movement of the main body when being stored into the housing. 45. Incidentally, a numeral 8 is a controller having a touch panel, a key switch, etc., and a printing operation on the rolled paper 1 is carried out in response to a command of the controller 8. 46. An operation of the printing apparatus having the above structure is now described by referring to FIG. 1 to FIG. 3B. As shown in FIG. 1, a large space can be provided for replacement of the rolled paper 1 or removal of jammed paper if the rolled paper 1 is positioned temporarily on the second holder 2a of the rolled-paper holder 2, allowing the work to be carried out very easily when inserting a leading end of the rolled paper 1 into a feeding port (not shown in the figure) of the printer unit 3, or removing jammed paper in the printer unit 3. Also, when the rolled paper 1 is held on the first holder 2b of the rolled-paper holder 2 with the main body of the apparatus returned to the normal printing work position, as shown in FIG. 2, a space between the rolled paper 1 and the printer unit 3 is reduced substantially. Replacement of the rolled paper 1 or removal of the jammed paper need not be carried out in this position, so that a reduction in size of a printer unit portion composed of the rolled-paper holder 2, the printer unit 3, the cutter unit 4, etc. is realized. 47. Furthermore, as shown in FIG. 3A and FIG. 3B, the rolled paper 1 positioned temporarily on the second holder 2a of the rolled-paper holder 2 makes contact with the rolled-paper thruster 7 (FIG. 3A) when the main body of the apparatus is shifted from the paper setting position for the rolled paper toward the normal printing work position. The rolled paper 1 is disengaged from the second holder 2a to rotationally or slidingly move to the first holder 2b along a sloped edge of the rolled-paper holder 2 (FIG. 3B) when the main body is further shifted, so that the rolled paper 1 can be restored to the position for carrying out printing with a simple return of the main body to the original position, thereby enabling replacement of the rolled paper 1 and removal of jammed paper easily and in a short time. Hence, the above structure can prevent a paper jam caused by a working error during replacement of the rolled paper 1 and an incomplete removal of papers jammed in and around the printer unit. 48. Although in the present embodiment the main body of the apparatus is constructed so as to be openable on an axis at its lower end, this is not an exclusive arrangement, and the same effect is attainable by constructing it to be openable on an axis located at an upper end or at either right or left side of the upper end. The present embodiment can also take up slack of the rolled paper 1, because the rotating direction and the moving direction of the rolled paper 1, in its rotational movement from the paper setting position to the printing work position, are in a relationship so as to rewind the rolled paper 1.

Second exemplary embodiment 49. FIG. 4 depicts a structure of a printing apparatus of a second exemplary embodiment of the present invention. Any components having the same structure as the first exemplary embodiment are assigned the same reference numerals and their descriptions are omitted. 50. In the figure, a guide unit 5 in a shape of duct comprises a first guide member 5a, which is attached onto a back surface of a cover 10 provided to cover a part of or the entirety of a main body of the apparatus, and a second guide member 5b, which is provided on the main part of the apparatus. Closing the cover 10 by revolving it on an axis 10a composes the guide unit 5 in shape of a duct. 51. Also, since a printed paper 1a touches its leading end with the first guide member 5a provided on the back surface of the cover 10, at most of the time, as the rolled paper 1 is supported on the rolled-paper holder 2 so that it has a curled end toward the cover side, a paper jam due to the recording paper 1a being caught at its leading end is prevented by smoothing the surface roughness of the first guide member 5a, or by reducing the contact area with the provision of a plurality of ribs, or by using an electrically conductive material such as metal, etc. to discharge static electricity charged on the recording paper 1a. 52. With the above-described structure, the recording paper 1a can be smoothly and positively taken out of the discharge port 6, jammed paper can be easily and positively removed, if it ever occurs, by simply opening the cover 10, and a paper jam due to incomplete removal of jammed papers is prevented. 53. Although in the described embodiment the cover is constructed so as to be openable on an axis at its lower end, this is not an exclusive arrangement, and the same effect is attainable by constructing it to be openable on an axis located at an upper end or at either the right or left side of the upper end.

Third exemplary embodiment 54. FIG. 5 is a structural drawing of a printing apparatus of a third exemplary embodiment of the present invention, showing a main body of the apparatus in its open position. Any components having the same structure as the second exemplary embodiment are assigned the same reference numerals and their descriptions are omitted. 55. A numeral 11 represents a movable rolled-paper holder for rotatably supporting a roller shaft 9 of the rolled paper 1. A numeral 12 represents a frame for supporting a printer unit 3, cutter unit 4 and a guide unit 5. A numeral 13 represents a shaft attached to the frame 12 and supporting the movable rolled-paper holder 11. Accordingly, the movable rolled-paper holder 11 is rotatably attached to the frame 12 with the shaft 13 as the axis of rotation. 56. The movable rolled-paper holder 11 is depicted by a chain double-dashed line to represent the movable rolled-paper holder 11 in a position for setting the rolled paper 1, or a second position. A continuous line represents a first position for printing on the rolled paper 1. The rolled paper 1 can be easily replaced when the movable rolled-paper holder 11 is in the second position, since a large space is made available over the printer unit 3 in the same way as in FIG. 1 for the first exemplary embodiment. 57. When carrying out printing on the rolled paper 1, the movable rolled-paper holder 11 is moved manually from the second position to the first position, or, as an alternate way, in the same manner as the first exemplary embodiment, the movable rolled-paper holder 11 may be moved from the second position to the first position along with a movement of the main body from an open position to a closed position by providing a rolled-paper thruster 7 (not shown in FIG. 5). 58. While the roller shaft 9 is made of a material in the shape of a cylinder or tube, it can be a cause of paper jams if the diameter is small, because the rolled paper 1 is usually curly paper. If the diameter is large, on the contrary, an increase in size of the apparatus is forced, as the rolled paper 1 also increases in diameter. An appropriate diameter to prevent a serious curl of the rolled paper is 15 mm or larger, and preferably between 35 mm to 40 mm to prevent habitually curly paper.

Fourth exemplary embodiment 59. A fourth exemplary embodiment of the present invention is described by referring to FIG. 6 to FIG. 9C. 60. FIG. 6 is a structural drawing depicting a construction of a printing apparatus of the fourth exemplary embodiment of the present invention, FIG. 7 is a structural drawing depicting a main body of the apparatus in its open position, FIG. 8 is a partially sectioned front view, and FIG. 9A to FIG. 9C are structural drawings depicting the construction of a discharge port. 61. In FIG. 6, a numeral 1 represents rolled paper which is axially supported by a roller shaft 9 as well as a rolled-paper holder 14 provided on a back surface of a main body of the apparatus.I It is cut by a cutter unit 4 according to a printed length after having been printed with a printer unit 3. Also, printed recording papers 1a and 1b, cut by the cutter unit 4 according to the printed length, are led toward a discharge port 16 under their own weight by passing through an L-shaped guide unit in the form of duct. FIG. 7 depicts the main body of the apparatus with its backside in an open position, as it is integrally constructed to be rotatable with the rolled-paper holder 14 and a part of the L-shaped guide unit 15 as one piece. 62. Two links of a chain 17 are hung as projections from a ceiling surface of the L-shaped guide unit 15 in the vicinity of its distal end, so that when a piece of paper in a shape depicted as a recording paper 1a, which is seriously curled as it has been rolled at a center part of the rolled paper 1, falls down, it is prevented from flying out of a discharge port 16 as it is caught by the chain links 17. Since these chain links 17 are shaped like a bead curtain, as in FIG. 8 when viewed from the front, the inside of the discharge port 16 is readily observable to detect the presence of printed output at a glance. The printed output is easily pulled out by inserting a hand without an obstruction to the printed output. 63. The projection can be cord-like, a belt-like object or a stick-shaped object hanging down, instead of the chain links 17, as a matter of course, in order to attain the same effect. Also, the chain links 17 may be positioned as deep inside of the discharge port 16 as possible, within the boundary of maintaining its functional effect as a stopper, and have the length shortened at the same time in order to prevent damage due to mischievous haul of the chain links 17. Furthermore, the chain links 17 are preferably made of electrically conductive material, from the viewpoint of avoiding clinging between the recording papers 1a and 1b due to static electricity. 64. Next, the discharge port 16 is provided with a stopper 18, and when a piece of paper in a shape as shown by a recording paper 1b, which is slightly curled as it has been rolled at an outer part of the rolled paper 1, falls down, it is prevented from flying out of the discharge port 16 as it is caught by the stopper 18. Also, the stopper 18 is constructed to have projections at both sides of the discharge port 16 to provide a wide opening at the center and its vicinity, as shown in FIG. 8 and FIG. 9A to FIG. 9C. 65. With the simple structure as described above, the chain links 17 or the stopper 18 can positively prevent the recording papers 1a and 1b from flying out, even if the printed output is of an irregular shape (varied in length). In this way, a printing apparatus can be constituted without employing the transfer means of the prior art, so as to be capable of preventing paper jams, as well as realizing a simplified apparatus. 66. An end part 15A of the L-shaped guide unit 15 is provided on its bottom surface with a plurality of ribs 19 having a convex shape at their tips, and the entire bottom surface is inclined toward the side of the discharge port 16.I Its lowest part is located at a height nearly equal to or slightly higher than a center area of the discharge port 16, so that a drop of water entering inside due to condensation, rain, washing, etc. is led along the slope on the bottom surface, and collected water is drained through the center area of the discharge port 16. A numeral 17a represents a hole for mounting a chain link 17 on the end part 15A. 67. The bottom surface may be provided with a channel or a hole for drainage at a lowermost location to discharge the collected water to the outside, and the stopper 18 can be provided also at a center area of the discharge port 16 in that case. Since the tip of the rib 19 is formed in a convex shape and asymmetrically, as shown in FIG. 9C, it destroys the balance of the water drop to prevent it from remaining on the tip of the rib 19, whereas a water drop tends to stay on the tip of the rib 19 due to the surface tension if it is symmetrical. Thus, it can quickly reinstate a condition of no water drops remaining on at least the tip of the rib 19, even if water gets inside due to rain, washing, etc., so as to avoid wetting of the printed output and paper jams due to wet paper. 68. Furthermore, a back surface of the end part 15A of the L-shaped guide unit 15 is provided with a plurality of ribs 20 in a direction generally perpendicular to the discharge direction of paper, as shown in FIG. 9A, with their tips sloped toward the bottom surface. All of the ribs 20 are laterally inclined from an approximate center of the back surface in a breadth direction, so that they disperse water entering the inside both downwardly and laterally, and prevent the water from spattering upwardly in the L-shaped guide unit 15. This enables the apparatus to be used outdoors.

Fifth exemplary embodiment 69. A fifth exemplary embodiment is described by referring to FIG. 10 to FIG. 12. 70. FIG. 10 is a structural drawing depicting a printing apparatus of the fifth exemplary embodiment of the present invention in an open position, FIG. 11 depicts a side view, and FIG. 12 is a partially sectioned drawing as viewed from the front. Since the present embodiment is similar to the third exemplary embodiment, any components of the same structure are assigned with the same reference numerals and their descriptions are omitted. Also, those components assigned with numerals 16, 17 and 18 have the same structures as the fourth exemplary embodiment. 71. The above structure can also alleviate paper jams and prevent the recording papers 1a and 1b from flying out of a discharge port 16, in the same way as the fourth exemplary embodiment. And, removal of a jammed paper is easy, as shown in FIG. 10, if it even ever occurs. 72. FIG. 13A depicts an enlarged side view of a cutter unit 4 of the present embodiment, and FIG. 14 depicts an enlarged front view of the cutter unit 4 of the present embodiment. A cutter adapter 23 in the figures is an adapter for mounting the cutter unit 4 onto a printer unit 3. The cutter unit 4 comprises a stationary blade 21 and a movable blade 22 (not shown in FIG. 13A) which cut a recording paper 1c. A guide 24 is attached to the cutter unit 4 in order to prevent the recording paper 1c from becoming jammed after it is cut. 73. The guide 24 is now described by referring to FIG. 13B and FIG. 15. FIG. 13B depicts the structure of FIG. 13A, but from which the guide 24 is deleted in order to describe the function of the guide 24. FIG. 15 also depicts a perspective view of the guide 24. Letters F, B, R and L in the figure indicate directions of the front, the back, the right side and the left side, respectively. 74. Sheet metal is used for the guide 24 of the present embodiment, but the thickness is not depicted as it is disregarded because of a very thin material. 75. There is a concern that a cut recording paper 1d which has a serious curl can be caught by the cutter unit 4 without the guide 24, as shown in FIG. 13B, but this is avoidable by adopting the guide 24.

Sixth exemplary embodiment 76. FIG. 16 is a fragmentary view of a sixth exemplary embodiment of the present invention. This embodiment adopts a cover 25 for a discharge port 6 of the fifth exemplary embodiment. With adoption of the cover 25, recording papers after having been cut are prevented from flying out, and the printing apparatus is able to effectively avoid rain water and dust from entering into the apparatus, even if it is placed outdoors.

Seventh exemplary embodiment 77. An operation of a seventh exemplary embodiment of the present invention is described. 78. FIG. 17A to FIG. 17D are typical drawings depicting an operation of a printing apparatus of a seventh exemplary embodiment of the present invention. In FIG. 17A to FIG. 17D, numerals 1c, 21, 22, 26 and 27 represent a recording paper, a stationary blade, a movable blade, a roller and a printer head, respectively. A normal printing operation is carried out by pressing the recording paper 1c against the printer head 27 with the roller 26 in rotary motion during printing while also transferring the paper simultaneously, followed by discharging the paper after it is cut with the stationary blade 21 and the movable blade 22. 79. FIG. 17A depicts an initial condition of a stand by period, FIG. 17B depicts a condition wherein the recording paper 1c is transferred in a forward direction after a predetermined amount of time has elapsed during the stand by period, FIG. 17C depicts a condition wherein the paper 1c is transferred in a reverse direction, and FIG. 17D depicts a condition wherein an automatic cutter is activated. The recording paper 1c is sent forward with a rotation of the roller 26, in FIG. 17B, and the recording paper 1c is returned backward with a reverse rotation of the roller 26 in the next FIG. 17C so as to prevent the recording paper 1c from being stuck completely with the printer head 27 or the roller 26 by temporarily freeing the recording paper which begins to stick with them. In FIG. 17D, the movable blade 22 is activated so as to protect component parts of an automatic cutter mechanism from oxidation, corrosion, hardening of grease, etc. 80. The operation described above is able to prevent a paper jam caused by a complete sticking of the recording paper 1c, which is liable to occur in case of a long stand-by period before a succeeding printing operation, or if it is used in an environment of high temperature and high humidity, etc. regardless of the stand-by time. 81. In the above description, the forward direction is meant to be a direction to which the recording paper 1c is transferred during the printing operation, and it is the right side in FIG. 17A to FIG. 17D. The reverse direction is a direction opposite to the forward direction. Also, any spot located in the forward direction and any spot located in the reverse direction with respect to a basic position may be referred to as downstream side and an upstream side, respectively, from now on. 82. Although in the described exemplar operation of the present embodiment, the recording paper 1c is transferred once in the forward direction after the predetermined time is elapsed, and it is cut following the transfer in the reverse direction, the same effect is also attainable by transferring the recording paper 1c once in the reverse direction after elapse of the predetermined time, and then transferred in the forward direction after it is cut.

Eighth exemplary embodiment 83. FIG. 18A to FIG. 18D are typical drawings depicting an operation of a printing apparatus of an eighth exemplary embodiment of the present invention. A letter A in the figures indicates a backside of a cutter. 84. An operation of a eighth exemplary embodiment of the present invention is now described along with FIG. 18A to FIG. 18D. FIG. 18A depicts an initial condition of a stand-by period, FIG. 18B depicts a condition wherein the recording paper 1c is transferred in a forward direction after a predetermined time has elapsed during the stand-by period, FIG. 18C depicts a condition wherein the recording paper 1c is transferred in a reverse direction and stepped with a leading end of the recording paper 1c located at a position downstream of the backside of the cutter, and FIG. 18D depicts a condition wherein an automatic cutter is activated. The recording paper 1c is sent forward with a rotation of the roller 26, in FIG. 18B, and the recording paper 1c is returned backward with a reverse rotation of the roller 26 to a position where the leading end of the recording paper 1c does not exceed the backside of the cutter in the next FIG. 18C, so as to prevent the leading end of the recording paper 1c from being cut by a subsequent cutting operation as well as a paper jam in an insertion port at the backside of the cutter during a paper transferring operation after the cutting. 85. Hence, paper jams caused by complete sticking, as described above, can be prevented by temporarily freeing paper which begins to stick with the printer head 27 or the roller 26 by rotating the roller 26 forward and backward, in the same manner as the operation of the seventh exemplary embodiment. Component parts of a paper transfer mechanism and an automatic cutter mechanism can also be protected from oxidation, corrosion, hardening of grease, etc.

Ninth exemplary embodiment 86. FIG. 19A to FIG. 19E are typical drawings depicting an operation of a printing apparatus of a ninth exemplary embodiment of the present invention. 87. Since FIG. 19A to FIG. 19D depict the same conditions as FIG. 17A to FIG. 17D in the seventh exemplary embodiment of the present invention, they are not described below. FIG. 19E depicts a condition where a recording paper 1c is transferred in the forward direction to the initial position (a condition in the start of a stand-by period), and a change in position of the recording paper 1c after a series of the above operations can be reduced substantially by transferring it in the forward direction in order to absorb backlash in gears that constitute the paper transfer mechanism. It also has the effect of preventing paper jams in the same way as the seventh exemplary embodiment, as a matter of course.

Tenth exemplary embodiment 88. A tenth exemplary embodiment of the present invention is described in the same manner by referring to FIG. 20A to FIG. 20E. Since FIG. 20A to FIG. 20D depict the same conditions as FIG. 18A to FIG. 18D in the eighth exemplary embodiment of the present invention, they are not described below. FIG. 20E depicts a condition where a recording paper 1c is transferred in the forward direction to the initial position (a condition in the start of a stand-by period), and a change in position of the recording paper 1c after a series of the above operations can be reduced substantially by transferring it in the forward direction in order to absorb backlash in gears that constitute the paper transfer mechanism. As a matter of course, it also has effect of preventing paper jams in the same way as the eighth exemplary embodiment.

Eleventh exemplary embodiment 89. FIG. 21A and FIG. 21B are typical drawings depicting an operation of a printing apparatus of an eleventh exemplary embodiment of the present invention. 90. In FIG. 21A and FIG. 21B, the same component elements as those of FIG. 17A to FIG. 17D are assigned with the same reference numerals, and their descriptions are omitted. Numerals 28, 28a and 29 represent a cutter housing, a paper exit of the cutter housing 28 and a paper discharge guide, respectively. 91. FIG. 21A depicts an initial condition of a stand-by period, in which a slightly curled recording paper 1c is hanging by adhesion on the paper exit 28a of the cutter housing 28 after having been cut, and FIG. 21B depicts a condition where a paper feeding operation has been done after a predetermined time interval during the stand-by period after the cutting. The paper advancing operation of paper 1c after lapse of the predetermined time has the function of pushing out the adhering recording paper 1e. Accordingly, a printed recording paper, after having been cut, can be discharged, even if it is jammed within the apparatus.

Twelfth exemplary embodiment 92. FIG. 22 is a perspective view depicting a structure of a printing apparatus of a twelfth exemplary embodiment of the present invention, in which numeral 1c is a recording paper, numeral 27 is a printer head for printing characters or figures on the recording paper 1c, numeral 26 is a roller for transferring the recording paper by making contact with the printer head 27, numeral 31 is a stepping motor for rotating the roller 26, and a numeral 30 is a paper transfer gear for transferring rotary motion of the stepping motor 31 to the roller 26. The roller 26, the stepping motor 31 and the paper transfer gear 30 constitute a transfer means. 93. FIG. 23 is an operational flowchart during a stand-by period in the same exemplary embodiment. 94. An operation of the twelfth exemplary embodiment is described by referring to FIG. 22 and FIG. 23. 95. When the printing apparatus is placed in a stand-by position, it waits for a predetermined time, and rotates the stepping motor 31 in the forward direction for a step of N1 when the predetermined time has elapsed in order to transfer the recording paper 1c in the forward direction. It then rotates the stepping motor 31 in the reverse direction for a step of N2 to transfer the paper 1c in the backward direction. Finally, again it rotates the stepping motor 31 in the forward direction for a step of N3 to transfer the recording paper 1c in the forward direction before terminating the stand-by operation. Here, the forward direction is meant to be a direction shown by an arrow in FIG. 22, and the reverse direction is a direction opposite to it. 96. The printing apparatus derived as above transfers the recording paper in the forward and the reverse directions in every predetermined interval during the stand-by period, and prevents the recording paper 1c from being stuck completely with the printer head 27 or the roller 26 by temporarily freeing paper that begins to stick, so as to avoid a paper jam caused by adhesion and to prevent grease used for the components constituting the paper transfer mechanism from hardening. The printing apparatus also provides effect of avoiding disfigurement of characters at the beginning of subsequent printing, since it absorbs backlash that occurs in the paper transfer gear 30 by rotating the stepping motor 31 in the forward direction, in the reverse direction, and again in the forward direction. 97. In this exemplar operation of the present embodiment, although the stepping motor is rotated in the reverse direction and then rotated in the forward direction again, after having rotated in the forward direction when the predetermined time elapsed during the stand-by period, the same effect is also attainable by rotating the stepping motor first in the reverse direction and then in the forward direction thereafter. Also, a D.C. motor can be utilized in place of the stepping motor 31, as it is capable of performing the same function in combination with an encoder. Moreover, the recording paper may be transferred by providing a roller for transferring paper in addition to the roller 26, and delivering it with the driving force of the motor. These variations are also applicable to thirteenth and fourteenth exemplary embodiments described below.

Thirteenth exemplary embodiment 98. FIG. 24 is an operational flowchart during a stand-by period in a thirteenth exemplary embodiment of the present invention. A structure of the present embodiment is identical to that of the twelfth exemplary embodiment, which is shown in FIG. 22. 99. In the present embodiment, when a printing apparatus is placed in a stand-by position, it waits for the lapse of a predetermined time, takes a measurement of a latest ambient temperature after the predetermined time has elapsed, and adjusts a further waiting time according to the temperature. For instance, it waits for a time of T1 if the measured temperature is low, waits for a time of T2 if it is normal, and waits for a time of T3 if it is high. After that, it rotates a stepping motor 31 forward for a step of N1 to transfer a recording paper 1c in the forward direction in the same way as described in the twelfth embodiment. It then rotates the stepping motor 31 backward for a step of N2 to transfer the recording paper 1c in the reverse direction. Finally, it rotates the stepping motor 31 forward for a step of N3 to transfer the recording paper 1c in the forward direction, and terminates the stand-by operation. 100. The printing apparatus derived as described above reduces the electric power it consumes in driving the stepping motor 31 for the stand-by operation, and minimizes the trace that is left behind on the surface of the recording paper 1c due to friction between the printer head 27 and the recording paper 1c with the forward and the backward rotations of the stepping motor 31 by reducing the number of operations of the stepping motor 31 with an increase of the time of T2, since it takes a longer time for the recording paper 1c to stick with the printing head 27 or the roller 26 when the ambient temperature is normal. The printing apparatus also has the effect of avoiding a paper jam caused by adhesion and preventing grease used for the components constituting the paper transfer mechanism from hardening, as it prevents the recording paper 1c from being stuck completely with the printer head 27 or the roller 26 by temporarily freeing the paper that begins to stick, by increasing the number of operations of the stepping motor 31 with a decrease of the time of T1 and T2, since it takes a relatively shorter time for the recording paper 1c to stick with the printing head 27 or the roller 26 when the ambient temperature is either low or high. 101. Although a determination of the ambient temperature is made for the three levels of low, normal and high, in this exemplar operation of the present embodiment, a better effect can be achieved if it is further divided into more levels.

Fourteenth exemplary embodiment 102. FIG. 25 is an operational flowchart during a stand-by period in a fourteenth exemplary embodiment of the present invention. A structure of the present embodiment is identical to that of the twelfth exemplary embodiment, which is shown in FIG. 22. 103. When a printing apparatus is placed in a stand-by position, it waits for the lapse of a predetermined amount of time, and, after the predetermined amount of time has elapsed, it proceeds into any one of processes A, B or C according to previously memorized information as to changes in magnitude of movement of the recording paper 1c when the stepping motor 31 has rotated forward and backward. A magnitude of movement of the recording paper 1c changes when the stepping motor 31 rotates forward and backward, because there are cases in which the recording paper 1c moves a different magnitude due to a variation in the finish condition of the roller 26 and the load on the transfer system from the recording paper 1c, even if the number of forward steps and the number of reverse steps of the stepping motor 31 are the same. There are three cases, i.e., the magnitude of movement is larger in the forward rotation, the magnitude of movement is larger in the backward rotation, and the magnitude of movement is the same between the forward and the backward rotations. 104. If magnitude of movement of the recording paper 1c is larger in the forward rotation than in the backward rotation, the stepping motor 31 is rotated forward for a step of N1, followed by backward rotation for a step of N1N2a, followed finally by forward rotation for a step of N2. A magnitude represented by the letter a corresponds to a change in the movement of the recording paper 1c by the forward and the backward rotations of the stepping motor 31. 105. Also, if the magnitude of movement of the recording paper 1c is the same in the forward rotation and in the backward rotation, the stepping motor 31 is rotated forward for a step of N1, followed by backward rotation for a step of N1N2, followed finally by forward rotation for a step of N2. 106. Also, if the magnitude of movement of the recording paper 1c is larger in the backward rotation than in the forward rotation, the stepping motor 31 is rotated forward for a step of N1, followed by backward rotation for a step of N1N2a, followed finally by forward rotation for a step of N2, and the stand-by operation is terminated 107. The printing apparatus derived as described above provides the effect of preventing a paper jam due to adhesion of the recording paper, and avoids shifting of a starting position of printing in the subsequent printing operation after resumption from the stand-by state by moving the recording paper to its original position by varying a number of steps for the forward and backward rotations depending on the finish condition of the roller and the load on the transfer system of the paper when rotating the stepping motor 31 forward, backward and forward after the lapse of a predetermined amount of time during a stand-by period. 108. As has been described with the exemplars in the first through the fourteenth embodiments, the printing apparatus of the present invention is provided with: easy replacement of a rolled paper; a guide unit openable from a cutter unit to a discharge port; a structure without a transfer means by enabling it to prevent cut recording paper from flying out of the discharge port; an operation for preventing adhesion of the recording paper to a printing head or to a roller; and, prevention of a paper jam by thrusting out the recording paper stuck to the cutter unit, in addition to other effects as described in the individual exemplary embodiments. 109. As has been described, the present invention is able to realize a printing apparatus of a small size for which replacement of rolled paper and removal of jammed paper can be carried out easily with a considerably simple structure, and to provide a printing apparatus of a small size with a considerably simple structure that can reliably deliver a printed output of even an irregular shape (varied in length) to a discharge port while alleviating the likelihood of a paper jam. 110. Furthermore, the present invention is able to realize a highly reliable printing apparatus of a small size which alleviates a paper jam in a succeeding printing operation, and avoids impairment to the operation of a paper transfer mechanism and a cutter mechanism, even when a stand-by state continues for an extended time period, and under such severe environmental conditions as high temperature and high humidity, or low temperature and low humidity, etc. 111. Accordingly, the printing apparatus is fit for not only household use, but also business use that requires high reliability, and it is also suitable as a printing apparatus for outdoor use since it has a structure protected well against rain, etc., and adaptable to changes of the ambient temperature.