KR20020035735A - Printing Machine - Google Patents

Abstract

PURPOSE: To provide a printer capable of accurately judging the feed state of printing paper. CONSTITUTION: The printer is equipped with a tractor 5 for feeding printing paper along a predetermined route, a roller 17 coming into contact with the printing paper to revolve by the angle corresponding to the moving distance of the printing paper, a rotary code wheel 20 revolved by the same angle as the roller 17 and having a large number of parts to be detected formed thereto on the concentric circle centering around the center of revolution at a predetermined pitch, and a photoelectric sensor 21 for detecting the parts to be detected to output a detection signal at each time when the printing paper moves by a predetermined distance.

Description

Printing Machine

The present invention relates to a printing apparatus having a function of detecting a conveyance situation of printing paper.

As a printing apparatus capable of high speed printing, there exists a dot printer mainly used for business, for example. In such a conventional dot printer, a roller which rotates by an angle corresponding to the moving distance of the printing paper in contact with the printing paper, and a tachometer which rotates together with the roller, and monitors the voltage output from the tachometer, It was a structure which detects jam.

However, the above-mentioned conventional dot printer has a problem that the conveyance state of printing paper cannot be judged with high accuracy.

That is, with the recent development of printing technology, printing apparatuses are required to increase printing speed and to improve printing quality. For example, the printing misalignment at the time of double printing is requested | required, and for this, it is necessary to grasp | ascertain the moving distance of printing paper, and to perform positioning. In addition, it is not enough to detect the jam of the printing paper completely while the jam of the printing paper, and the jam is immediately detected when the conveying speed becomes slow beyond the tolerance, and the waste of the printing paper and printing time is eliminated. It is desired to suppress as much as possible.

By the way, in the structure which judges the conveyance state of printing paper based on the output voltage of a tachometer like the said conventional dope printer, although it was possible to detect the jam when the printing paper in conveyance stopped completely, It is impossible to detect the conveyance speed and conveyance distance of printing paper with high precision. As a result, control of the conveying apparatus cannot be performed in accordance with the actual conveyance situation of the printing sheet, and improvement of printing quality from the viewpoint of the conveying accuracy of the printing sheet is not achieved.

BRIEF DESCRIPTION OF THE DRAWINGS The conceptual explanatory drawing explaining the whole structure of the printing apparatus which concerns on this invention.

2 is a front view of the tractor shown in FIG.

3 is a plan view of the tractor shown in FIG.

Fig. 4 is a sectional view seen from the arrow A-A in Fig. 3;

FIG. 5 is a conceptual explanatory diagram of the printing unit shown in FIG. 1; FIG.

FIG. 6 is a front view of main parts of the linear motor shown in FIG. 5; FIG.

Fig. 7 is a plan view of the main parts of the linear motor shown in Fig. 5;

Fig. 8 is an explanatory diagram of a pin block provided in the print head shown in Fig. 5;

FIG. 9 is a circuit block diagram of a control unit provided in the printing apparatus shown in FIG.

Fig. 10 is a flowchart for explaining a paper conveying processing procedure executed by the MPU shown in Fig. 9;

11 is a front view of a linear scale in another embodiment.

12 is a front view of a linear scale in still another embodiment.

<Explanation of symbols for the main parts of the drawings>

4: printing part

5: tractor

8: printing paper

11: stepping motor

12: belt

17: roller

20: rotating cord wheel

21: photoelectric sensor

31: print head

52: print pin

55: MPU

56: ROM

57: RAM

61, 71: linear scale

62, 72: negative

63: slit

73: reflector

The present invention was devised under the above circumstances, and an object thereof is to provide a printing apparatus capable of accurately determining the conveyance status of printing paper.

Moreover, an object of this invention is to provide the printing apparatus which can control the stop position of a printing sheet with high precision.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, the following technical means are calculated | required.

According to the first aspect of the present invention, there is provided a paper conveying unit for conveying printing paper along a predetermined path, a roller which contacts the printing paper and rotates by an angle according to the moving distance of the printing paper, and rotates by the same angle as the roller. A rotating body having a plurality of to-be-detected portions having a predetermined pitch on a concentric circle centered on a rotation center, and a detecting portion to detect a to-be-detected portion and output a detection signal each time the print sheet moves a predetermined distance An apparatus is provided.

According to a preferred embodiment, it has a movement speed determination unit that determines whether or not the movement speed of the printing paper is appropriate based on the detection signal from the detection unit.

According to another preferred embodiment, the paper conveying unit uses the stepping motor as a drive source, and the detecting unit outputs a detection signal whenever the printing paper moves by a distance corresponding to one step of the stepping motor.

According to the second aspect of the present invention, a paper conveying unit for conveying printing paper along a predetermined path, a detecting unit detecting an actual moving distance of the printing paper, and a paper conveying unit are controlled based on the detection result by the detecting unit. There is provided a printing apparatus comprising a control section for controlling a stop position of a printing sheet.

According to a preferred embodiment, the control unit conveys the print paper at a low speed by a distance corresponding to the difference when the actual moving distance detected by the detector is less than a predetermined distance or a predetermined ratio less than the moving distance to be conveyed by the paper conveying unit. Instruction is given to the paper conveying unit, and according to the instruction, the paper conveying unit conveys the print paper, and as a result, the actual moving distance detected by the detection unit is a predetermined distance or a predetermined ratio from the moving distance that should be conveyed by the paper conveying unit. When there is little abnormality, it is judged that the abnormality has occurred in paper conveyance.

According to the present invention, a paper conveying unit for conveying printing paper along a predetermined path, a roller which contacts the printing paper and rotates by an angle according to the moving distance of the printing paper, rotates by the same angle as the roller and centers the rotation center. On the concentric circle, a plurality of to-be-detected parts were provided with a rotating body having a predetermined pitch, and a detecting part for outputting a detection signal each time the print sheet moved by a predetermined distance by detecting the to-be-detected part, and based on the detected signal from the detecting part. The conveyance situation of printing paper can be judged with high precision.

In addition, according to the present invention, the paper conveying unit conveys the printing paper along a predetermined path, the detecting unit detecting the actual moving distance of the printing paper, and the paper conveying unit based on the detection result by the detecting unit to stop the printing paper. Since the control part which controls a position is provided, since the actual moving distance of printing paper is fed back to a paper conveyance part, the stop position of printing paper can be controlled with high precision.

Other features and advantages of the present invention will become more apparent from the following description of embodiments of the invention.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of this invention is described concretely with reference to drawings.

1 is a conceptual explanatory diagram for explaining the overall configuration of a printing apparatus according to the present invention. This printing apparatus includes a hopper 1, paper pressing rollers 2a and 2b, a platen roller 3, a printing unit 4, a tractor 5, a guide roller 6, and a stacker 7 have.

The printing paper 8 made of continuous paper is conveyed along the predetermined path from the hopper 1 to the stacker 7 by the tractor 5. The tractor 5 is driven via the belt 12 by the stepping motor 11. The printing paper 8 is printed by the printing unit 4.

2 is a front view of the tractor 5. 3 is a plan view of the tractor 5. FIG. 4 is a sectional view seen from the arrow direction A-A in FIG. 2-4, the detection mechanism for detecting the conveyance distance of the printing paper 8 is mainly shown, and the other part has shown the outline. The protrusions 16 protruding from the conveying belt 15 of the tractor 5 are inserted into holes formed in the widthwise end of the printing paper 8, and the printing paper 8 is conveyed in the direction of the arrow in FIG. .

The disk-shaped roller 17 made of an elastic material such as natural rubber or synthetic rubber is rotated by an angle proportional to the moving distance of the printing paper 8 in contact with the printing paper 8. At this time, since the lid 18 attached to the tractor 5 so as to be openable and closed, the injuries of the printing paper 8 are favorably suppressed by the lid 18, and the printing paper 8 and the roller ( The contact state of 17) is secured. In addition, the cover 18 is abbreviate | omitted in FIG.

The rotating cord wheel 20 is fitted and fixed to the rotating shaft 19 which supports the roller 17, and the rotating cord wheel 20 rotates integrally with the roller 17. As shown in FIG. In the rotary cord wheel 20, a plurality of protrusions 20a protrude radially from the center, and transmissive photoelectric sensors 21 are disposed on both sides in the axial direction of the rotary cord wheel 20. The photoelectric sensor 21 has a light transmitting portion 21a and a light receiving portion 21b. If nothing exists between the light transmitting portion 21a and the light receiving portion 21b, the light from the light transmitting portion 21a is directed to the light receiving portion 21b. It is received by. Therefore, when the roller 17 rotates with the movement of the printing paper 8, and the rotation code wheel 20 rotates integrally with the roller 17, the projection 20a of the rotation code wheel 20 is transmitted to the light transmitting portion. A state in which light from 21a is blocked and a state in which light is not blocked are alternately generated, and a detection signal of a period inversely proportional to the moving speed of the printing paper 8 is output from the light receiving portion 21b.

5 is a conceptual explanatory diagram of the printing unit 4. The print section 4 includes a print head 31, a linear motor 32, a linear encoder 33, a moving object 34, a belt 35, pulleys 36a and 36b, a guide rod 37, and a coil. Springs 38a and 38b are provided.

Stoppers 39a and 39b, which are slidably fitted to the guide rod 37, are provided at the tip end of the movable body 34, and the print head 31 and the movable body 34 move along the guide rod 37. It is possible. The coil springs 38a and 38b are fitted to the guide rod 37 so as to be slidable. The linear motor 32 moves the movable body 34 reciprocally linearly in the direction of the arrow of FIG. With the movement of the movable body 34, the belt 35 connected to the movable body 34 moves, and the print head 31 connected to the belt 35 with the movement of the belt 35 moves with the movable body 34. Move in the reverse direction. Therefore, when the moving body 34 moves to the right direction in FIG. 5, the printing head 31 moves to the left direction, and the coil spring 38b moves to the stopper of the printing head 31 and the moving body 34. 39b) sandwiched and compressed. On the contrary, when the moving body 34 moves to the left direction in FIG. 5, the printing head 31 moves to the right direction, and the coil spring 38a moves to the stopper of the printing head 31 and the moving body 34. Between 39a) and compressed.

6 is a front view of main parts of the linear motor 32. 7 is a plan view of main parts of the linear motor 32. The linear motor 32 is provided with a plurality of pairs (six pairs in this embodiment) of permanent magnets 41a and 41b which form a pair facing each other at predetermined intervals, and between each pair of permanent magnets 41a and 41b. The coil support part 42 of the moving body 34 is located in this. The coil support part 42 is provided with a plurality of coils 43 (6 in this embodiment), and each coil 43 is located in the gap between the pair of permanent magnets 41a and the permanent magnets 41b. . Of these coils, two coils 43 at both ends function as constant speed coils, and the remaining four coils 43 function as inverting coils. The inversion coil is a coil mainly for imparting a driving force or a brake force to the print head 31 when the print head 31 accelerates and decelerates to reverse the moving direction, and the constant speed coil is used when the print head 31 performs constant speed travel. It is mainly a coil for imparting a driving force to the printing head 31. When the direction of movement of the print head 31 is reversed, the coil spring 38a or the coil spring 38b is compressed and deformed by the driving force applied by the linear motor 32. Thereby, the elastic restoring force of the coil spring 38a or the coil spring 38b acts on the print head 31, and the moving direction of the print head 31 is reversed in an instant.

8 is an explanatory diagram of a pin block provided in the print head 31. The pin block 51 has a predetermined interval in the direction inclined with respect to both the moving direction of the print head 31 and the direction orthogonal thereto, as indicated by the arrow B in FIG. A plurality of printing pins 52 (12 in this embodiment) are provided on a diagonal line at a predetermined pitch. A plurality of pin blocks 51 are disposed in the print head 31 along the moving direction of the print head 31. The printing paper 8 is conveyed in the direction of an arrow C in FIG. By driving of the printing pin 52, printing is performed by pressing the printing paper 8 to the platen roller 3 via the ink ribbon (not shown).

9 is a circuit block diagram of a control unit of the printing apparatus according to the present invention. The control unit includes an MPU 55, a ROM 56, a RAM 57, and an interface circuit 58. These MPU 55, ROM 56, RAM 57, and interface circuit 58 are connected to each other by a bus line. The interface circuit 58 is connected to a coil 43 of the linear motor 32, a photoelectric switch (not shown) of the linear encoder 33, a light receiving portion 21b of the photoelectric sensor 21, and a stepping motor 11. have.

The microprocessor unit (MPU) 55 controls the entirety of the printing apparatus.

The ROM (read only memory) 56 stores data such as a control program and a set value which the MPU 55 should execute.

A random access memory (RAM) 57 is used as a work area of the MPU 55 or the like and stores various data.

The interface circuit 58 controls the exchange of signals between the MPU 55 and the linear motor 32, the linear encoder 33, the photoelectric sensor 21, and the stepping motor 11.

Next, the operation will be described. 10 is a flowchart for explaining a paper conveyance processing procedure executed by the MPU 55. As shown in FIG. This process is executed by the MPU 55 every predetermined time. First, the MPU 55 determines whether paper conveyance is necessary (S1). That is, when printing is performed, the conveyance of the printing paper 8 and the printing by the printing head 31 are alternately performed. Therefore, it is checked whether or not the printing paper 8 needs to be transported at this time.

If paper feeding is required (S1: Yes), the MPU 55 drives the stepping motor 11 at a predetermined normal speed (S2). Specifically, the MPU 55 supplies a driving pulse to the stepping motor 11 to drive the stepping motor 11 by a predetermined number of steps. In the present embodiment, when the character is printed, the driving of the 24 steps and the driving of the 36 steps are alternately repeated as the stepping motor 11 is driven by 24 steps, and then driven by 36 steps. When printing the image data, the step of driving the stepping motor 11 by 24 steps is repeated.

Next, the MPU 55 determines whether the printing paper 8 has been conveyed for a predetermined distance (S3). Specifically, the MPU 55 counts the number of pulses of the detection signal from the photoelectric sensor 21 and calculates the actual moving distance of the printing paper 8 based on the count number, which is for example a stepping motor. It is checked whether or not it corresponds to 24 steps of (11). At this time, since the pulse may not be detected by the conversion of the detection signal at the beginning and the end of the count, the allowable range of the error is set in advance, and if the print paper 8 is conveyed for more than 22 steps in two steps, printing is performed. It is determined that the paper 8 has been conveyed a predetermined distance.

If the printing paper 8 is not conveyed by the predetermined distance (S3: No), the MPU 55 drives the stepping motor 11 at a lower speed than the normal speed (S4). Specifically, the MPU 55 calculates the uncarrying distance and drives the stepping motor 11 by the number of steps corresponding to the distance. At this time, since the stepping motor 11 is driven at a low speed, the detachment state of the stepping motor 11 can be eliminated, and the possibility of conveying the printing paper 8 normally increases.

Next, the MPU 55 determines whether the printing paper 8 has been conveyed for a predetermined distance (S5). The specific operation at this time is the same as in step S3.

If the printing paper 8 is conveyed a predetermined distance (S5: YES), the MPU 55 drives the printing unit 4 to perform printing (S6), and this process ends.

In step S5, if the printing paper 8 is not conveyed a predetermined distance (S5: NO), the MPU 55 notifies that a jam has occurred (S7) and ends this process. This notification is performed by displaying, for example, letters or symbols that a jam has occurred on a display screen (not shown) of the display device provided in the printing apparatus. Of course, in addition to this notification, a release instruction or the like may be displayed. Instead of the display by the display device or in addition to the display, an alarm sound such as a chime or a buzzer may be sounded.

In step S3, if the printing paper 8 is conveyed a predetermined distance (S3: YES), it progresses to step S6.

In step S1, if paper conveyance is not needed (S1: No), this process ends.

Thus, the tractor 5 which conveys the printing paper 8 along a predetermined path, the roller 17 which contacts the printing paper 8, and rotates by the angle according to the moving distance of the printing paper 8, Printing by detecting the rotating code wheel 20 and the detected part of the rotating code wheel 20 which rotate by the same angle as the roller 17 and formed the plurality of detected parts in a predetermined pitch on a concentric circle centered on the rotation center. Since the photoelectric sensor 21 which outputs a detection signal every time the sheet | seat 8 moves a predetermined distance is provided, the conveyance state of the printing paper 8 can be judged with high precision based on the detection signal from the photoelectric sensor 21. have.

Moreover, the tractor 5 which conveys the printing paper 8 along the predetermined path | route, the photoelectric sensor 21 which detects the actual moving distance of the printing paper 8, and the detection result by the photoelectric sensor 21 Since the MPU 55 which controls the stop position of the printing paper 8 by controlling the tractor 5 on the basis is provided, since the actual moving distance of the printing paper 8 is fed back to the tractor 5, the printing paper 8 Can be controlled with high precision.

Moreover, when the actual moving distance detected by the photoelectric sensor 21 is less than a predetermined distance less than the moving distance to be conveyed by the tractor 5, the printing paper 8 should be conveyed at a low speed by the distance corresponding to the difference. To the tractor 5, and according to the instruction, the tractor 5 conveyed the printing paper 8, and as a result, the actual moving distance detected by the photoelectric sensor 21 was conveyed by the tractor 5; If it is determined that the abnormality has occurred in the conveyance of the paper when it is smaller than a predetermined distance by the movement distance, the stop position of the printing paper 8 can be controlled with high precision and the stepping motor 11 is separated by the low speed driving. And the possibility of conveying the printing paper 8 normally increases.

Moreover, in the said embodiment, although the conveyance state of the printing paper 8 was detected by the combination of the rotation code wheel 20 and the photoelectric sensor 21, as shown in FIG. 11, the linear scale 61 and the transmission photoelectricity were shown. The conveyance state of the printing paper 8 may be detected by the combination of the sensors. The linear scale 61 is formed by radially forming a plurality of linear slits 63 on the thin disc 62. The slit 63 is processed by the method of etching etc., for example, and is formed in the very fine pitch of about 80 micrometers on the circumference centering on the center of the original plate 62, for example.

Alternatively, as shown in FIG. 12, the conveyance state of the printing paper 8 may be detected by the combination of the linear scale 71 and the reflective photoelectric sensor. The linear scale 71 is formed by radially forming a plurality of linear reflectors 73 on the disc 72. The reflector 73 is formed by, for example, printing or the like, and is formed on a circumference centered on the center of the original plate 72 at a very fine pitch of, for example, about 80 μm. Disc 72 is configured to absorb light from a photoelectric sensor. Of course, you may provide the absorber which absorbs the light from a photoelectric sensor instead of the reflector 73. In this case, what reflects the light from a photoelectric sensor as the original plate 72 may be used.

When the linear scale 61 or the linear scale 71 is used, more accurate detection can be performed than when the rotary cord wheel 20 is used. For example, when one step of the stepping motor 11 corresponds to a printing density of 180 dpi, the slits 63 or so that one cycle of detection pulses are output from the photoelectric sensor every time the printing paper 8 moves by 0.141 mm. When the pitch of the reflector 73 is set, a detection pulse of one cycle can be obtained every time the stepping motor 11 is driven by one step, so that highly accurate detection can be performed and control is very easy. That is, by comparing the drive pulse of the stepping motor 11 and the detection pulse from the photoelectric sensor, the conveyance state of the printing paper 8 can be judged by one step unit of the stepping motor 11, By controlling the stepping motor 11 based on the detection pulse from the photoelectric sensor, the conveyance speed and conveyance distance of the printing paper 8 can be controlled with high precision and easily. Therefore, the jam can be detected quickly before the printing paper 8 completely stops due to the decrease in the conveying speed of the printing paper 8.

In addition, in the said embodiment, although the whole printing apparatus was controlled by one MPU 55, you may provide multiple MPU, and in that case, the function sharing of each MPU is arbitrary.

In addition, in the said embodiment, although continuous paper was used as the printing paper 8, this invention can be utilized effectively even if a printing paper is cut paper.

Of course, the specific structure of the printing apparatus in the said embodiment is an example, and this invention is not limited to this specific structure.

As described above, according to the present invention, there is provided a paper conveying unit for conveying printing paper along a predetermined path, a roller which contacts the printing paper and rotates by an angle according to the moving distance of the printing paper, and rotates by the same angle as the roller. Since a rotating body having a large number of detected parts at a predetermined pitch is formed on a concentric circle centered on the rotation center, and a detecting part which outputs a detection signal every time a print sheet moves by a predetermined distance by detecting the detected part, detection from the detecting part The conveyance state of printing paper can be judged with high precision based on a signal.

In addition, according to the present invention, the paper conveying unit conveys the printing paper along a predetermined path, the detecting unit detecting the actual moving distance of the printing paper, and the paper conveying unit based on the detection result by the detecting unit to stop the printing paper. Since the control part which controls a position is provided, since the actual moving distance of printing paper is fed back to a paper conveyance part, the stop position of printing paper can be controlled with high precision.

Claims (5)

A paper conveying unit for conveying printing paper along a predetermined path; A roller which contacts the printing paper and rotates by an angle according to a moving distance of the printing paper; A rotating body rotating at the same angle as the roller and having a plurality of detected parts at a predetermined pitch on a concentric circle centered on a rotation center; And a detection unit for outputting a detection signal each time the print sheet moves by a predetermined distance by detecting the detection unit. The printing apparatus according to claim 1, further comprising a moving speed determining unit that determines whether or not the moving speed of the printing sheet is appropriate based on the detection signal from the detecting unit. The said paper conveyance part is a drive source of Claim 1 or 2, And the detection unit outputs a detection signal each time the printing sheet moves by a distance corresponding to one step of the stepping motor. A paper conveying unit for conveying printing paper along a predetermined path; A detection unit for detecting an actual moving distance of the printing sheet; And a control unit for controlling the stop position of the printing sheet by controlling the paper conveying unit based on the detection result by the detecting unit. 5. The printing paper according to claim 4, wherein the control section sets the printing paper by a distance corresponding to the difference when the actual moving distance detected by the detecting unit is smaller than a predetermined distance or a predetermined ratio than the moving distance to be conveyed by the paper conveying unit. Instructs the paper conveying unit to convey the paper at a low speed, and according to the instruction, the paper conveying unit conveys the printing paper, and as a result, the actual moving distance detected by the detecting unit should be conveyed by the paper conveying unit. The printing apparatus characterized by the above-mentioned determining that abnormality has occurred in conveyance of paper, when it is less than predetermined distance or predetermined ratio rather than the moving distance.