JPH0335568Y2 - - Google Patents

Description

[Detailed Description of the Invention] The printer of the invention will be explained according to the following items.

A. Field of industrial application B. Overview of the invention C. Prior art a. General background b. Conventional printer D. Problem that the invention attempts to solve E. Means for solving the problem F. Example a. Main body case [Figure 1] b Platen [Figs. 1 to 5] c Paper nipping mechanism [Figs. 1 to 5] c-1 Configuration c-1-a Paper nipping section [Figs. 1 to 5]
Figure] c-1-b Optical path [Figures 1 to 5] c-1-c Paper sandwiching member [Figures 1 to 5
Figure] c-1-d Paper guide [Figures 1 to 5
Figure] c-1-e Detection means [Figures 1 to 5
Figure] c-2 Operation c-2-a Paper sandwich preparation [Figure 4 A, B,
C] c-2-b Acceptance of print paper [4th
Figures B, C,] c-2-c Paper clip [Figure 4C, Figure 5] d Ink ribbon [Figure 3] e Thermal head [Figure 3] f Control circuit [Figure 7] g Control operation [Figure 6] G. Effect of the invention (A. Field of industrial application) The present invention relates to a new printer. More specifically, it relates to a printer that performs a predetermined printing operation on print paper while the print paper is wrapped around a platen, and the leading edge of the print paper is fixed to the platen by a paper clipping member provided on the printer. To provide a new printer which is capable of directly detecting whether or not print paper has fallen out of the paper nipping member after it has been removed, without providing a dedicated detection means for this purpose. That is.

(B Overview of the invention) The present invention detects whether or not the printing paper has fallen off the platen as another detection target in a printer that performs a predetermined printing operation on the printing paper with the printing paper wrapped around the platen. It is possible to directly detect the paper by using a detection means for the paper, and thereby it is possible to stop the printing operation when a dropout of printing paper is detected without increasing the number of detection means. This is how it was done.

(C Prior Art) (a General Background) There are various types of printers such as thermal printers, pen printers, dot printers, and inkjet printers.
Depending on the form of printing paper used, it can be roughly divided into those that use so-called cut paper and those that use continuous paper.

In printers that use cut paper for printing paper, printing or printing is generally performed with the printing paper wrapped around the platen. This is done by fixing the leading end of the printing paper to the platen using a paper nipping member provided on the platen, and rotating the platen in this state.

Therefore, in such printers, after the leading edge of the print paper is fixed to the platen,
It is necessary that the print paper be wound in a predetermined state around a predetermined portion of the platen until the platen comes to a position where the print paper wrapped around the platen is taken out;
In the unlikely event that print paper should fall off the platen, it is necessary to be able to detect this and immediately stop the operation.

(b Conventional Printer) In a conventional printer, whether or not print paper has fallen off the platen is detected in the following manner, for example.

That is, the elapsed time from the time when the print paper was fed toward the paper nipping member of the platen is measured, and if the elapsed time exceeds a certain time and the paper is not ejected, the print paper is moved toward the platen. It is now determined that the paper has fallen out of the printer, and measures such as stopping the printing operation are now being taken.

(Problem to be solved by invention D) The method of detecting whether or not print paper has fallen off the platen in the conventional printer described above indirectly detects whether or not the paper has fallen off from the platen based on the detection result regarding the elapsed time after paper feeding. Since it is a method of detecting information, it has the problem of lacking accuracy.

Moreover, with such a detection method, the fact that the printing paper has fallen off is usually detected after a certain amount of time has elapsed from the time when the paper has fallen off. Therefore, during this time, the print paper that has fallen off the platen may get caught and become entangled with members arranged around the platen, or the print head may print on the surface of the platen. In other words, there is a risk that a secondary operation error may occur.

Therefore, it is conceivable to provide a detection means for directly detecting whether or not the printing paper has fallen off, and to immediately stop all printing operations when the falling off of the printing paper is detected.

However, since various members or mechanisms are arranged inside the printer, especially around the platen, it is often difficult to provide a detection means in such a position. If a printer is installed, problems arise, such as pushing up the price of the printer.

(E. Means for Solving Problems) In order to solve the above-mentioned problems, the printer of the present invention detects when the leading edge of the print paper is inserted to a predetermined position on the platen and sends a predetermined signal. In addition, when a predetermined signal is output from the detection means, the leading edge of the paper is fixed to the platen by a paper nipping member provided on the platen, and necessary information is provided after printing is started. A control circuit is provided that stops the printing operation when a signal different from the above signal is output until printing is completed.

Therefore, according to the present invention, it is possible to directly detect whether or not the print paper has fallen off the platen by using the detection means necessary to fix the leading edge of the print paper to the platen. When the omission is detected, the printing operation can be stopped immediately.

(F. Embodiment) The details of the printer of the present invention will be explained below according to the embodiment shown in the attached drawings. In the embodiment shown in the drawings, the printer of the present invention is applied to a thermal color printer 1.

(a Main body case) [Figure 1] Reference numeral 2 in the figure is the main body case of the printer 1, and the main body case 2 is formed into a substantially box shape.
The inside of the printer is provided with a platen, a paper sandwiching mechanism provided on the platen, a thermal head, and other components, a control circuit, etc., which will be described later, and an ink ribbon cassette containing an ink ribbon, which will be described later, can be detachably installed. It's getting old.

(b Platen) [Figures 1 to 5] 3 is a platen. The platen 3 is formed into a substantially cylindrical shape and is placed at a predetermined position inside the main body case 1, and both ends of its shaft 4 are rotatably supported by support members (not shown).

(c Paper nipping mechanism) [Figures 1 to 5] 5 is a paper nipping mechanism, and the paper nipping mechanism 5 includes a paper nipping part provided on the outer peripheral surface of the platen 3;
An optical path formed in the platen 3, a paper guide that guides insertion of the leading edge of the print paper into the paper nipping part, and detecting that the leading edge of the print paper has been inserted to a predetermined position in the paper nipping part. It consists of a detection means, a paper nipping member for fixing the leading end of the print paper to the paper nipping part, and the like.

(c-1 Configuration) (c-1-a Paper holding part) [Figures 1 to 5] 6 is a sheet of paper formed by cutting out a part of the outer peripheral surface of the platen 3 along the longitudinal direction. It is a holding part. The paper holding portion 6 is formed to have a substantially L-shape when the platen 3 is viewed from the axial direction. 7 is a paper pressing surface of the paper nipping section 6, and 8 is an abutting surface.

A relatively shallow groove portion 9 is formed in a portion of the sheet pressing surface 7 of the sheet holding portion 6 that intersects with the abutting surface 8 in the left-right direction of the sheet pressing surface 7, that is, in the left-right direction of the plane of the paper in FIG. In the figure, the right side of the paper surface is the right side, and the left side is the left side. In addition, the lower side of the paper surface in FIG. ) from a position close to one end to a position close to the other end.

Reference numeral 10 denotes a cutout portion formed by cutting out approximately the center of the edge of the paper pressing surface 7 on the groove portion 9 side. Relatively shallow notch recesses 11a, 11b, and 11c are formed in the center portion and both left and right end portions of the abutment surface 8 of the paper holding portion 6 in the left-right direction. These cutout recesses 11a, 11b and 1
1c is formed to have a certain length in the left-right direction.

Further, an optical path relay recess 12 is formed in the central notch recess 11a, which is further notched deeply toward the rear.

(c-1-b Optical Path) [FIGS. 1 to 5] 13 is an optical path formed in the platen 3. As shown in FIG.
The optical path 13 extends parallel to the axial direction of the platen 3 through a portion adjacent to the abutment surface 8 of the paper holding portion 6 in a portion close to the outer peripheral surface of the platen 3, and has both ends thereof. Openings are provided at both end faces of the platen 3. The optical path 13 is opened on both left and right side surfaces of the optical path relay recess 12 at a central position in the axial direction. A light-shielding piece of a light-shielding body, which will be described later, is arranged in the optical path relay recess 12, and the optical path 13 can be blocked or opened by the light-shielding piece.

(c-1-c Paper pinching member) [Figures 1 to 5] 14 is a paper presser bar. The paper holding bar 14 is formed to be slightly longer than the axial length of the platen 3,
It is formed so that its cross-sectional shape is approximately shaped, and mounting pieces 15, 15 bent downward at a substantially right angle are integrally formed at both ends. Pressing members 16, 16 made of a material with a high coefficient of friction, such as rubber, are fixed to the lower surface of the paper presser bar 14, except for the central portion, by means of fixing means such as adhesive. In addition, 17, 17 are the above-mentioned mounting pieces 15,
This is a pin insertion hole formed in the upper part of 15.

Reference numerals 18 and 18' designate arm plates that support the paper presser bar 14, and the arm plates 18 and 18' are rotatably supported on both left and right end surfaces of the platen 3, and have a substantially angular shape when viewed from the side. They are formed in a shape that is symmetrical to each other. Projecting pieces 19, 19' are integrally formed so as to project upward from the upper end edges of the front parts of the arm plates 18, 18'.
Support pins 20, 20' are fixed to the upper part of 9' so as to extend in the left-right direction and pass through the projecting pieces 19, 19'.

Reference numerals 21 and 21' (only one of the arm plates 18 is shown in the drawing) are insertion holes formed approximately in the center of the arm plates 18 and 18' in the front and back direction; ', and 23, 23' (only one arm plate 18 is shown in the drawing).
are spring engaging holes arranged at the front portions of the arm plates 18, 18' at a certain distance from each other in the front-rear direction.

The arm plates 18, 18' have their insertion holes 2
Arm support shafts 24 and 2 protrude outward from both left and right end surfaces of the platen 3 at 1 and 21', respectively.
It is supported by the platen 3 by being passed through the tip of the platen 4'. That is, the arm support shafts 24, 24' protrude from approximately the center of both the left and right end surfaces of the platen 3 and the position corresponding to the paper pressing surface 7 of the paper holding section 6. The tip end is connected to the insertion hole 21 formed in the arm plate 18, 18'.
It is a narrow diameter portion having a diameter slightly smaller than the diameter of 21'. Further, the end portions of the arm support shafts 24, 24' are inserted into the insertion holes 21, 21' of the arm plates 18, 18', and in this state, the arm support shafts 24, 24' are inserted.
Screws 26, 26' are screwed into screw holes 25, 25' (only one arm support shaft 24 is shown in the drawing) formed at the tip of the arm 4'.
27, 27' are washers.

Therefore, the arm plates 18, 18' are supported so as to be rotatable about the portions of the left and right end surfaces of the platen 3 through which the arm support shafts 24, 24' are inserted.

The paper presser bar 14 has pins 20, 20' protruding from protruding pieces 19, 19' of the arm plates 18, 18' into the pin insertion holes 17, 17 of the mounting pieces 15, 15 at both ends thereof. By being penetrated,
It is supported in such a manner that it can rotate to some extent relative to the arm plates 18, 18'.

It should be noted that pins 15a, 15a, which protrude outward from the lower parts of the mounting pieces 15, 15 of the paper presser bar 14,
15a is provided, and the pin is connected to the arm plate 1.
8, 18' are engaged with elongated holes 18a, 18'a formed therein, thereby limiting the rotational range of the paper presser bar 14 to a certain range. That is, even if the paper press bar 14 is rotated to some extent, the press members 19, 19 can always come downward when pressing the leading edge of the paper.

28, 28' are arm plate tension springs, and these arm plate tension springs 28, 2
Reference numeral 8' denotes the spring engaging holes 22, 22' and 23, 2 formed at one end in the arm plates 18, 18'.
Spring locking hole 22, 2 on the front side of 3'
2', and the other end is engaged with spring engagement pins 29, 29' protruding from both end surfaces of the platen 3. As a result, the arm plate 18,1
Reference numeral 8' denotes a rotating force that constantly tries to rotate the paper presser bar 14 in the clockwise direction in FIG.
It is biased with a rotational force that presses it against.

(c-1-d Paper Guide) [Figures 1 to 5] 30 is a paper guide. The paper guide 30 has a lower piece 31 formed in a narrow band shape and is bent rearward from the front edge of the lower piece 31, and gradually extends from the lower piece 31 toward the tip. It consists of an upper piece part 32 that is integrally formed and extends diagonally so as to move away from each other, and spring engagement holes 33, 33 are formed at both ends of the lower piece part 31. 34
a, 34a from the central part of the rear end edge of the lower piece part 31, from a position spaced apart from each other to some extent;
b and 34c are arms projecting rearward from positions near both ends of the lower side portion 31;
The tips of the arms 34a, 34a, 34b, and 34c are bent downward at a substantially right angle, and the tips of the bent portions are further bent at a substantially right angle toward the rear.

35a, 35b and 35c are the paper guides 3 mentioned above.
This is a fulcrum plate constituting a rotation fulcrum part of 0, and hook parts 36, 36, . At both ends of each fulcrum plate 35a, 35b and 35c, holes 37, 37 for screw insertion are provided.
...is formed.

The paper guide 30 is provided with the paper holding part 6 on the platen 3 such that both ends of the lower piece 31 thereof are positioned above the upper edges of the front ends of the arm plates 18, 18'. Paper pressing surface 7
and its arms 34a, 34
A, 34b, and 34c are arranged so that the downwardly bent portions of the tip portions a, 34b, and 34c at right angles are in contact with the front side surface of the groove portion 9 formed in the paper pressing surface 7. Then, with the paper guide 30 disposed as described above, the fulcrum plates 35a, 35b are placed at respective predetermined positions on the bottom surface of the groove 9.
and 35c are screwed into the bottom surface of the groove 9 through screw insertion holes 37, 37, . . . formed in these screws 38, 38, .
Fixed. That is, the fulcrum plate 35a is fixed at a position corresponding to the central notch 11a formed in the abutment surface 8 of the paper holding part 6 on the bottom surface of the groove 9, and the fulcrum plates 35b and 35c are also fixed at a position corresponding to the abutment surface 8 of the paper holding part 6. Notch recesses 11 formed at both left and right ends of 8
It is fixed at the position corresponding to b and 11c. As a result, the arms 34a, 34a of the paper guide 30,
The tips of 34b and 34c are fulcrum plates 35a, 35
The hooks 36, 36, . . . are located below the hooks 36, 36, .

Therefore, the paper guide 30 has its arm 34
The tips of a, 34a, 34b and 34c are groove portions 9.
front side and fulcrum plates 35a, 35b and 35c
Since the hooks 36, 36, . . . are prevented from coming off with a certain amount of play, it is possible to rotate using the tip that is prevented from coming off as a rotation fulcrum. be made possible.

Of the arms of the paper guide 30, the arms 34a and 34a at the center are located between the pressing members 16 of the paper presser bar 14, and the arms 34b and 34c at both left and right ends are located between the pressing members 1 and 16, respectively.
6, 16 (see Figure 1).

39, 39' are tension springs, one end of which is engaged with the spring engagement holes 33, 33 formed at both ends of the lower piece of the paper guide 30, and the other end of which is engaged with the arm plate 15, Spring engagement holes 22, 22' and 23, 2 formed in 15'
3' on the rear side 23, 23'. Therefore, the paper guide 30 is always biased with an elastic force such that it is pressed against the paper pressing surface 7 of the paper nipping section 6.

(c-1-e Detection Means) [Figures 1 to 5] Reference numeral 40 denotes a light shielding body made of a plate spring material. The light shielding body 40 includes a mounting piece 40a formed in a substantially T-shape when viewed from above, and the mounting piece 40a is bent rearward from the front edge of the mounting piece 40a, and the mounting piece 40a gradually bends toward the tip. The front portion of the elastic piece 40b is bent into a crank shape. A light-shielding piece 40c is arranged at the tip of the elastic piece 40b so that the elastic piece 40b is bent downward from one side edge at a substantially right angle, and its surface extends in a direction perpendicular to the left-right direction. is formed. 41,4
Reference numeral 1 denotes screw insertion holes formed at both end portions of the mounting piece 40a.

The front part of the mounting piece 40a of the light shielding body 40 is disposed in the notch 10 formed in the paper pressing surface 7 of the paper holding part 6 of the platen 3, and the rear part of the mounting piece 40a However, by inserting the screws 38, 38 to which the central fulcrum plate 35a is fixed into the screw insertion holes 41, 41, the fulcrum plate 35a is fixed to the bottom surface of the groove 9 in a state overlapping with the fulcrum plate 35a. be done. That is, the light shielding body 40 is disposed below the paper presser bar 14 between the pressing members 16 .

Therefore, the light shielding piece 40c of the light shielding body 40 is disposed within the optical path relay recess 12 formed in the abutment surface 8 of the paper clamping part 6 of the platen 3, and the light shielding piece 40c of the light shielding body 40
If the leading edge of the print paper is not inserted into the
As shown in FIGS. 4A and 4B, it is positioned so as to block the optical path 13.

Note that a hole 42 is formed in the bottom surface of the optical path relay recess 12 and is elongated in the front-rear direction. This hole 4
Reference numeral 2 is for allowing the light shielding piece 40c to move below the bottom surface of the optical path relay recess 12 when the elastic piece 40b of the light shielding body 40 is pressed downward by the leading edge of the paper.

Reference numeral 43 indicates a light projecting section made of a light emitting element such as a light emitting diode, and reference numeral 44 indicates a light receiving section consisting of a light receiving element such as a phototransistor. The light projecting section 43 and the light receiving section 44 are located on an extension of the axis of the optical path 13 when the platen 3 is rotated to the sheet feeding position, and are spaced apart from both ends of the platen 3 to some extent. The main body case 2
It is fixed to a mounting member (not shown) fixed to the side. When the platen 3 is rotated to the paper feeding position, the light projecting part 43, the light receiving part 44, and the optical path 13 are all located on the same axis, so unless there is something blocking the way, The light emitted from the light projecting section 43 passes through the optical path 13 of the platen 3 and can be irradiated toward the light receiving section 44 .

Note that the light projecting section 43 and the light receiving section 44 are connected to a control circuit of the printer, which will be described later.

(c-2 Operation) The paper nipping mechanism 5 configured as described above nip the leading end of the print paper as follows.

(c-2-a Paper nipping preparation) [Fig. 4 A, B, C] The paper presser bar 14 and the paper guide 30 are positioned at a position where the platen 3 can feed paper thereto (hereinafter referred to as the "feeding paper"). When the platen 3 is not in the paper feeding position, it is pressed against the paper pressing surface 7 of the paper nipping section 6, as shown in FIG. 4A, but the platen 3 is rotated to the paper receiving position. When you come,
As shown in FIGS. 4B and 4C, the paper is moved upward from the paper pressing surface 7.

That is, when the platen 3 is not at the paper receiving position,
The arm plates 18, 18' have tension springs 28,
Since it is receiving a tensile force of 28', the paper presser bar 1
4 is in a state in which the lower surfaces of the pressing members 16, 16 are brought into pressure contact with the sheet pressing surface 7 by the tensile force of tension springs 28, 28' urged on the arm plates 18, 18'. And with this,
The paper guide 30 also has tension springs 39, 39'.
, the lower surface of the lower piece 31 is brought into pressure contact with the paper pressing surface 7. Further, the light shielding body 40 has an elastic piece 40b.
Since no pressing force is applied to the platen 3, the light shielding piece 40c is positioned so as to block the central part of the optical path 13 of the platen 3, as shown in FIGS. 4A and 4B.

Therefore, when the platen 3 rotates to the paper receiving position, a roller 45 rotatably supported at the rear end of the arm plate 18 is moved by a cam (not shown) provided on the main body case 2 side to rotate the platen 3 to the paper receiving position. It is pressed approximately toward the axial center. Then, arm plate 1
8 is rotated in the counterclockwise direction in FIG.
It is moved integrally with 8. Incidentally, the right arm plate 18' is also rotated integrally with the arm plate 18'.
As a result, the paper presser bar 14 is
As shown in FIG. 2, the lower surfaces of the pressing members 16, 16 are moved upward away from the sheet pressing surface 7. Also, in this way, the arm plate 1
8, 18' are rotated, the paper guide 3
Both ends of the lower piece 31 of 0 are the arm plates 18, 18'
The paper guide 30 is also pressed from below by the upper edge of the front part of the arm plate 1.
8, 18' and the paper presser bar 14 together with the paper presser bar 14.

Thus, a space sufficient for inserting the leading end of the printing paper is formed above the paper pressing surface 7 of the paper nipping section 6 of the platen 3.

(c-2-b Acceptance of print paper) [Fig. 4B, C] Then, the leading edge of the print paper 46 is inserted between the paper pressing surface 7 and the paper guide 30 by an automatic paper feed mechanism (not shown). come. At this time, the leading end of the print paper 46 is attached to the arm 3 of the paper guide 30.
By being moved while contacting 4a, 34a, 34b, and 34c, the insertion direction is correctly guided.

(c-2-c paper clip) [Fig. 4C, Fig. 5] Then, when the leading edge of the print paper 46 is inserted, the elastic piece 40b of the light shield 40 touches the leading edge of the print paper 46, etc. As a result, it is pressed from the upper right direction. Then, the elastic piece 40b uses the connection part with the mounting piece 40a as a rotational fulcrum, and rotates as shown in FIG. 4C.
As shown in FIG. 3, it is rotated so as to be folded onto the mounting piece 40a. This causes the light shielding piece 40c to be displaced downward. That is, the light shielding piece 4c is moved from the position where it had been blocking the optical path 13 to the position where it opens the optical path 13. As a result, the light emitted from the light projecting section 43 is irradiated onto the light receiving section 44, so that a predetermined detection signal is output from the light receiving section 44, and this detection signal is input to the control circuit. Become. That is, it is detected that the leading edge of the print paper has been inserted to a predetermined position on the platen 3.

Note that the leading edge of the print paper 46 is the paper pressing surface 7.
and the arm portions 34a, 34a, 3 of the paper guide 30.
It can be inserted up to the position where the lower surfaces of 4b and 34c intersect.

As a result, the control circuit moves the cam (not shown) away from the arm plate 18 to a position where it does not press the roller 45, and the arm plates 18, 18' are returned to their original positions by the tensile force of the tension springs 28, 28'. be returned to. Therefore, the leading end of the print paper 46 is pressed against the paper pressing surface 7 by the pressing members 16, 16 of the paper presser bar 14. That is, the leading end of the print paper 46 is held between the paper pressing surface 7 of the platen 3 and the pressing members 16, 16 of the paper presser bar 14. In addition, the paper guide 30
The lower piece portion 31 and the arm portions 34a, 34a,
34b and 34c come to a position where the leading end surface of the printing paper 46 is pressed against the paper pressing surface 7.

Thus, the leading edge of the print paper 46 is pinched by the paper pinching mechanism 5, so that the print paper 46 is held by the platen 3.
It will be fixed at

As mentioned above, the arm plates 18, 18' are supported with some play on the arm support shafts 24, 24' on which they are supported, so some play may occur in the direction of rotation. However, due to this backlash, the pressing members 16, 16 of the paper presser bar 14 can come into substantially uniform contact with the leading end of the printing paper 46 over its entire length in the longitudinal direction. That is, when the paper presser bar 14 comes into contact with the paper pressing surface 7 in a one-sided manner, it automatically assumes the most stable posture, that is, a posture in which it is in contact with the paper pressing surface 7 over the entire length in the longitudinal direction. As such, the arm plates 18, 18' are slightly displaced while being pulled in either direction in the direction of rotation. Therefore, it is possible to prevent the paper presser bar 14 from being in a state of uneven contact.

Note that when the platen 3 rotates once and comes to the paper feeding position again, the paper presser bar 11 is moved as described above.
Since the paper guide 27 is separated upward from the pressing surface 4, the printed paper 43 can be taken out from the platen 3.

(d Ink ribbon) [Figure 3] 47 is an ink ribbon. The ink ribbon 4
7 is wound approximately in the shape of a roll paper, and both ends of the ink ribbon 7 are wound around a reel provided in an ink ribbon cassette (not shown) that is detachably attached to the main body case 2. It is designed to run as the one on the receiving side is rotated. Although not shown, on one side of the ink ribbon 47, a large number of ink layers each having an area slightly smaller than the area of the printing paper 46 are arranged at predetermined intervals along the running direction of the ink ribbon 47. The ink layer has, for example, one of three colors, cyan, magenta, and yellow, and is formed such that the three colors are arranged in a constant order.

Incidentally, the ink ribbon 47 formed in this way
When an ink ribbon cassette (not shown) is installed in a predetermined position in the main body case 2, the platen 3 and a thermal head, which will be described later, are arranged behind the platen 3 with one surface facing the platen 3. It has come to be located between.

(e Thermal head) [Figure 3] 48 is a thermal head, and the head board 48
A heating section 49 in which a large number of resistive heating elements (not shown) are arranged is attached to the tip of a. When the thermal head 48 prints on the print paper 46, the heat generating section 49 of the thermal head 48 passes through the ink ribbon 47 and the print paper 46 to the platen 46, as shown by the solid line in FIG.
When the printer is moved to a position where it is brought into contact with the outer peripheral surface of the printer under a predetermined pressure (hereinafter referred to as the "advance position") and no printing is performed, the heat generated by the The portion 49 is held at a position at a certain distance from the ink ribbon 47 (hereinafter referred to as the "retracted position").

Thus, the print paper 46 whose leading end is held between the platen 3 as described above is made to run while being in contact with the heat generating section 49 via the ink ribbon 47. Then, at the location where the ink ribbon 47 comes into contact with the heat generating portion 49, the ink at the position corresponding to the resistive heating element that is energized and generates heat is dissolved and transferred onto the print paper 46. Printing is thereby done.

(f Control Circuit) [FIG. 7] A control circuit 50 is provided inside the main body case 2 of the printer 1. This control circuit 50 receives various trigger signals inputted by operating an operation section (not shown) provided on the outer surface of the main body case 2 and detected by various detection means such as the light receiving section 44. In accordance with the detection signal, a command signal for causing a predetermined operating member to perform a predetermined operation is output.

This control circuit 50 controls the light receiving section 44
When a detection signal (hereinafter referred to as the "first detection signal") that is output when the light from the light projecting unit 43 is irradiated is inputted, the motor for driving the platen is set to a specified value. A command is output to the platen driving circuit 51 to rotate the ink ribbon 47 in the direction shown in FIG. When a detection signal (hereinafter referred to as a "second detection signal") that is output when light irradiation from the light projector 43 is interrupted is input, the platen drive circuit 51 stops the motor. The head moving circuit 52 outputs a command to that effect and also outputs a command to move the thermal head to the retreat position.

Incidentally, FIG. 6 shows an example of a control program executed by the control circuit.

(g Control operation) [Figure 6] Therefore, the printer 1 configured as described above
The control operation will be explained step by step according to the steps of the flowchart shown in FIG.

(a) "Preparation for printing" Prepare for printing by moving the platen 3 to the paper receiving position and the thermal head 48 to the retreat position.

(b) “Has the print button been pressed?” Print button 53 for starting printing
Checks whether or not is pressed, and if it is not pressed, waits until it is pressed.

(c) "Feed paper" When the print button 53 is pressed, a command is given to the paper feed drive circuit 54 that drives an automatic paper feed mechanism (not shown) to feed the print paper 46 stored in the paper tray.
is sent out toward platen 3.

(D) "Is the paper detection sensor on?" It is asked whether or not the first detection signal is output from the paper detection sensor, that is, the light receiving section 44 described above. Then, if the first detection signal is not output, wait for it to be output, and if it is output, proceed to the next step.

(E) "Perform paper nipping" When the first detection signal is output, the leading edge of the fed print paper 46 has been inserted to the predetermined position in the paper nipping section 6 provided on the platen 3. Therefore, as described above, the cam that was pressing the roller 45 of the arm plate 18 escapes, and the paper is pinched.

(F) "Carry out the beginning of the platen and the beginning of the ink ribbon." The platen drive circuit 51 is commanded to rotate the platen 3, and a predetermined portion of the print paper 46 wrapped around it generates heat in the thermal head 48. At the same time, a command is issued to the ink ribbon drive circuit 55 to cause the ink ribbon 47 to travel so that a predetermined portion of the ink layer of a predetermined color provided on the ink ribbon is placed on the thermal head 48. It is placed at a position facing the heat generating part 49.

(g) "Press the head to the platen" A command is issued to the head moving circuit 52 to move the thermal head 48 to the forward position.

(h) “Start printing” Start printing on the print paper 46.

This printing is performed by the thermal head 48 and the ink ribbon 47, as described above. The range that can be printed on the print paper 46 is divided into, for example, 784 lines along the running direction of the print paper 46, and the heat generation command for the heat generating unit 49 of the thermal head 48 is divided into 784 lines, for example. This is done every line. That is, printing by the thermal head 48 is performed line by line. When printing for one line is completed, the platen 3, print paper 46, and ink ribbon 47 are rotated or moved by an amount sufficient to feed the line for one line, and then the next line is printed.
Printing for each line is now performed.

(k) "Is the paper detection sensor on?" Inquires whether the first detection signal is output from the light receiving section 44. If the answer is "yes", proceed to step (sa); if the answer is "no", proceed to step (co). It should be noted that, until the platen 3 returns to the paper feeding position after paper nipping is performed, the portion of the platen 3 other than the optical path 13 is between the light projecting section 43 and the light receiving section 44. Therefore, the answer to step (k) during this period is always "no". Therefore, there is no need to proceed to step (sa) during this time.

(J) "Have all print lines been printed?" For example, the question is asked whether all of the 784 lines mentioned above have been printed. If the answer is ``yes'', that is, printing has been completed for the area to be printed, the step
If the answer is “No”, proceed to the above step (C).
This loop will be repeated until the answer is "yes".

(S) "Set flag" As mentioned above, this step is reached when the platen has returned to the paper receiving position and the answer in step (K) is "yes", that is,
This is a case where it is confirmed that the leading end of the print paper 46 is held between the platen 3. and,
In this step, a flag of "1" is set in the flag register.

(b) "Remove the head from the platen" Since it has been confirmed in step (c) that printing has been completed for all print lines, a command is issued to the head movement circuit 52 to move the thermal head 48 to the backward position. to move to.

(S) "Is the flag = 1?" Inquires whether the "1" flag is set in the flag register. As described above, if the first detection signal is output from the light receiving section 44 when the platen 3 is returned to the paper feeding position, it is confirmed that the print paper 46 has not fallen off the platen 3, and the Therefore, the "1" flag is set at step (sa), so the answer to this question is "yes".
In this case, proceed to step (T). However, when the second detection signal is output from the light receiving section 44 when the platen 3 is returned to the paper receiving position, the leading edge of the print paper 46 is not connected to the platen 3.
It is detected that the paper is not held by the paper holding part 6, and in this case, the paper does not pass through the step.
The "1" flag is not set in the flag register. Therefore, the answer in this case is "no",
Proceed to step (ce).

(C) "Sound jamming alarm" Lights up the alarm lamp 56 or sounds the buzzer 57 to notify that the print paper 46 has fallen off the platen 3.

(S) "Cancel printing" The rotation of the motor is stopped, the rotation of the platen 3 and the running of the ink ribbon 47 are stopped, and the printing operation is stopped.

(T) "Reset the flag" Set the flag set in the step (S) above to "0".

(H) "Has the platen rotated three times?" Inquire whether the platen 3 has rotated three times after the print button is pressed. That is, since this printer 1 is supposed to complete the entire printing operation by printing once for each of the three colors of the ink layer provided on the ink ribbon 47,
This question asks whether printing has been done for all three colors. For this purpose, platen 3
A counter 58 is provided to detect the number of rotations. If the answer to this question is "no", that is, if at least one color of print remains, the process returns to step (f), and if the answer is "yes", the process proceeds to step (t).

(2) "Feed the paper" Feed the printed paper out of the main body case 2 and return to step (a).

(G Effect of the invention) As is clear from the above description, the printer of the invention extends along the axial direction of the platen around which the paper is wound, and the leading edge of the paper is inserted into the platen to a predetermined position. In addition to forming an optical path that is blocked or opened, a light projecting section is provided at one of the positions on the main body side corresponding to both ends of the optical path, and a light receiving section is provided at the other, and a predetermined signal is output from the light receiving section. When the leading edge of the paper is fixed to the platen by the paper nipping member provided on the platen, and a signal different from the above signal is output after printing has started and until the necessary printing is completed. It is characterized by the provision of a control circuit that stops the printing operation.

In other words, the printer of the present invention detects whether or not the print paper has fallen off the platen until the leading edge of the print paper is inserted into the platen at a predetermined position, which is a necessary detection target for fixing the leading edge of the print paper to the platen. Detection is performed by using a detection means for detecting whether or not an error occurs.

Therefore, according to the present invention, it is possible to determine whether or not print paper has fallen off the platen without providing a dedicated detection means for detecting this.
Not only can it be directly detected, but also when the omission is detected, the printing operation can be stopped immediately to prevent the printing paper from jamming inside the printer or printing against the platen.

In the above-mentioned embodiment, when the leading edge of the print paper is inserted to a predetermined position on the platen, the light from the light projecting section is irradiated onto the light receiving section, so that the light is output from the light receiving section. Although the signal is set as a predetermined detection signal, in some cases, the light from the light emitter may be illuminated on the light receiver in advance, and the leading edge of the print paper may be placed at a predetermined position on the printer. It is also possible to cut off the light irradiation from the light projecting section to the light receiving section when the light receiving section is inserted up to that point, and to use the signal outputted from the light receiving section at this time as the predetermined detection signal.

Furthermore, in the embodiment described above, the light emitting section and the light receiving section are fixedly provided on the main body side, and whether or not the print paper falls off the platen is determined by rotating the platen to a position where paper is fed to the platen. However, by providing the light emitting part and the light receiving part on a member that rotates in synchronization with the rotation of the platen, it is possible to constantly detect whether or not the print paper has fallen out. It is also possible to do so.

In the embodiments described above, the present invention was applied to a thermal printer, but the present invention can be applied to various printers that perform printing with printing paper wrapped around a platen.

[Brief explanation of the drawing]

The drawings show an example of applying the printer of the present invention to a thermal printer. Figure 1 is a plan view showing the main parts of the printer with some parts omitted, and Figure 2 is an exploded view of the platen and paper nipping mechanism. 3 is a side view of the main parts of the printer shown in FIG. 1, and FIG. 4 shows the process of detecting insertion of the leading edge of paper in order from A to C. A cross-sectional view of the main part, FIG. 5 is a cross-sectional view of FIG.
6 is a flowchart showing an example of a control program by the control circuit, and FIG. 7 is a block diagram of the control circuit. Explanation of symbols, 1...Printer, 2...Main unit,
3...Platen, 13...Optical path, 14...Paper sandwiching member, 43...Light emitter, 44...Light receiver, 46
...Paper.

Claims (1)

[Claims for Utility Model Registration] Forming an optical path extending along the axial direction of a platen around which paper is wound and that is blocked or opened when the leading end of the paper is inserted to a predetermined position, A light emitting section is provided at one of the positions on the main body side corresponding to both ends of the optical path, and a light receiving section is provided at the other, and when a predetermined signal is output from the light receiving section, a paper sandwiching member provided on the platen is used. A control circuit is provided which fixes the leading end of the paper to the platen and stops the printing operation when a signal different from the above signal is output between the start of printing and the end of the required printing. printer.