JP2826694B2 - Serial printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial printer.

[0002]

2. Description of the Related Art FIG. 8 is a perspective view showing a main part of a serial printer. In the figure, 1 is a print head, and 2 is a carriage unit on which the print head 1 is mounted.
3 is a belt for moving the carriage unit 2 in the spacing direction, 4 is a DC motor for driving the belt 3, and 5 is a main shaft for supporting the carriage unit 2 and guiding the movement of the carriage unit 2. , 6 are sub shafts for guiding the movement of the carriage unit 2.

[0003] Reference numeral 7 denotes a slit disk fixed on the axis of the DC motor, and is provided with a plurality of slits in the circumferential direction. Reference numeral 8 denotes a photo sensor for detecting the slits of the slit disk 7, and by counting the number of slits,
The amount of rotation of the DC motor 4 can be recognized.
The position of the carriage unit 2 that moves as the C motor 4 rotates can be managed.

FIG. 9 is a side view of a serial printer showing a relationship between a print head and a medium, 9 is a platen arranged opposite to the print head 1, and 10 is a feed roller for conveying a medium 11 such as a passbook. When driven by a motor, the feed roller 10 rotates and feeds the clamped medium 11 between the print head 1 and the platen 9 to move the medium 11 to a print position. The print head 1 moves in the spacing direction with respect to the medium 11 by the mechanism described with reference to FIG. 8, and drives a pin (not shown) in synchronization with the movement to form dots. Was printed.

[0005]

However, the above-described conventional serial printer has the following problems. That is, when the number of dots forming a character becomes high, the number of pins driven simultaneously during printing increases, and the reaction force of the pin drive causes the carriage unit to float or bend, thereby causing the print head and the medium to move. Is wider than the head gap originally required for printing, which causes a problem that dot removal and print head pin breakage occur.

Further, this problem can be solved by extending the time for driving the pins. However, since the moving speed of the carriage must be decreased by the length of the pin driving time, the overall printing speed is reduced. It has the problem of going down. As described above, the present invention solves the problems of dot removal and print head pin breakage due to the widening of the head gap, and attempts to solve the problem by prolonging the pin drive time reduce the overall printing speed. This was done to solve the problem of increased time.

That is, an object of the present invention is to provide a serial printer capable of realizing high-speed printing without causing dot removal or bending of print head pins.

[0008]

In order to achieve this object, the present invention provides a carriage for mounting a print head, a carriage driving means for moving the carriage, a platen opposed to the print head, and a platen. Analyzes the maximum number of simultaneous drive pins for each line from print data sent to print in a serial printer equipped with platen drive means that adjusts the gap by moving the printer toward and away from the print head. Print data analyzing means, a carriage position managing means for storing a moving speed of the carriage according to the number of simultaneously driven pins, a pin driving time controlling means for storing a pin driving time corresponding to the moving speed of the carriage, and the print data The carriage moving speed corresponding to the maximum number of simultaneously driven pins analyzed by the analyzing means is determined by the carriage position tube. Means for controlling the carriage driving means and the pin driving time control means based on the read moving speed of the carriage to change the moving speed of the carriage and control the driving time of the print head pins according to the moving speed of the carriage. Control means for performing the control.

Further, the present invention provides a carriage on which a print head is mounted, a carriage driving means for moving the carriage, a platen opposed to the print head, and a direction for moving the platen toward and away from the print head. Print data analyzing means for analyzing the maximum number of simultaneous drive pins for each line from print data sent for printing in a serial printer having platen drive means for adjusting the gap by moving the A gap value corresponding to the maximum number of simultaneously driven pins analyzed by the print data analysis means from the gap position management means, and a platen based on the read gap value. It is characterized by comprising control means for controlling the driving means and changing the gap.

[0010]

According to the present invention having the above-described structure, the maximum number of simultaneous drive pins for each line is analyzed from print data sent for printing. Printing is performed with the speed set to the normal speed, and printing is performed at a slower moving speed of the carriage than usual for a row having a maximum number of simultaneous drive pins.

On the other hand, for a line having a small maximum number of simultaneous driving pins, printing is performed with a gap set according to the thickness of the medium. Perform printing with a reduction.

[0012]

An embodiment will be described below with reference to the drawings. FIG. 1 is a control block diagram of a serial printer showing a first embodiment of the present invention, and FIG. 2 is a side view showing a platen up / down mechanism mounted on the serial printer.
The configuration of the platen up / down mechanism will be described with reference to FIG. In FIG. 2, the print head 1, a mechanism (not shown) for moving the print head 1 in the spacing direction, a platen 9, a feed roller 10, and the like are the same as those described in FIGS. It is.

In FIG. 1, reference numeral 21 denotes an up / down (hereinafter, referred to as U / D) motor. A motor gear 22 and a slit disk 23 are fixed to a shaft of the U / D motor 21. Reference numeral 24 denotes a rack attached to the platen 9. The rack 24 supports the platen 24 so as to move up and down so that the platen 9 approaches and separates from the print head 1. And a rack gear portion 24a extending along the rack gear portion 24a. The racks 24 are attached to both ends of the platen 9 in the extending direction.

Reference numeral 25a denotes a motor gear 2 of the U / D motor 21.
2, a large gear 25b coaxial with the large gear 25a, a large gear 25c meshing with the small gear 25b, and a small gear 25d coaxial with the large gear and meshing with the rack gear 24a of the rack 24. The drive force generated by the U / D motor 21 is transmitted to the rack 24 by these gear groups, and the rotational motion of the U / D motor 21 is converted into the vertical motion of the rack 24. In addition, the rack 24 is a platen 9
Gears 25c and 2 are provided on both ends of the gears 25c and 2 to transmit the driving force to the other rack 24.
From 5d, a shaft extends along the platen 9 and a small gear is attached to the shaft, which is
Of the rack gear portion 24a. This allows
The driving force is simultaneously transmitted to the left and right racks 24, and the platen 9 can be moved up and down while maintaining the parallel state.

Reference numeral 26 denotes a photosensor for detecting the amount of rotation of the slit disk 23.
3 is provided with a plurality of slits along its circumferential direction. The slit is detected by the photo sensor 26 and the number of the slits is counted.
Thus, the position of the platen 9 that moves up and down by the rotation of the U / D motor 21 can be managed.

Reference numeral 27 denotes a ribbon protector bracket attached to the print head 1 so as to face the platen 9. The ribbon protector bracket 27 protects the print head 1 by contacting the platen 9 or the medium 11. A contact detection sensor 28 detects that the platen 9 or the medium 11 has contacted the lower surface of the ribbon protector bracket 27.

Next, the operation of the up / down mechanism of the platen 9 having the above configuration will be described. As an initial operation of the printer of the auto-gap system, an operation for storing the distance from the initial DOWN position of the platen 9 to the ribbon protector bracket 27 as basic data for the subsequent measurement of the medium thickness is performed.

That is, by sending a forward signal to the U / D motor 21 to rotate the U / D motor 21 in a predetermined direction, the platen 9 at an initial position, which is at a certain distance from the ribbon protector bracket 27, is moved to the ribbon protector. It is moved in the direction of the bracket 27. U / D motor 21
, The distance between the platen 9 and the ribbon protector bracket 27 becomes narrower,
Finally, the platen 9 and the ribbon protector bracket 27
Is in contact. The contact between the platen 9 and the ribbon protector bracket 27 indicates that the contact detection sensor 2
8, the rotation of the U / D motor 21 is stopped.

At this time, the number of slits detected by the feedback pulse from the photo sensor 26 until the U / D motor 21 starts rotating and the platen 9 contacts the ribbon protector bracket 27 is counted. Is stored as the distance from the initial position of the platen 9 to the ribbon protector bracket 27, and then the U / D motor 21 is rotated in the opposite direction to return the platen 9 to the initial position.

Next, when the medium is conveyed by the feed roller 10 and positioned between the print head 1 and the platen 9, the thickness of the medium is detected. That is, by sending a forward signal to the U / D motor 21, the U / D motor 2
1 is rotated in a predetermined direction, and the platen 9 in the initial position is rotated.
In the direction approaching the medium.

When the forward signal is continuously sent to the U / D motor 21, the medium is pushed up by the platen 9 and comes into contact with the ribbon protector bracket 27. This is detected by the contact detection sensor 28, and the rotation of the U / D motor 21 is started. Be stopped. At this time, the number of slits detected by the feedback pulse from the photo sensor 26 until the U / D motor 21 starts rotating and the medium comes into contact with the ribbon protector bracket 27 is counted. As described above, the distance from the initial position of the platen 9 to the ribbon protector bracket 27, which is stored before the U / D motor 21 starts rotating and the platen 9 contacts the ribbon protector bracket 27, is stored. The difference between the counted number and the counted number is obtained, and this difference is stored as the thickness of the medium.

Next, the U / D motor 21 is rotated by a predetermined amount in the direction opposite to the above, and the platen 9 is moved to the ribbon protector 27.
From the medium, and after providing an optimum gap L between the medium and the ribbon protector bracket 27 according to the medium thickness obtained as described above, the U / D motor 21 is stopped, and the platen is stopped. 9 is fixed. Next, position management of the print head 1 in the printing direction will be described with reference to FIG.

As described with reference to FIG. 8, the carriage unit 2 has the print head 1 mounted thereon, and the carriage unit 2 is caused to run along the main shaft 5 and the sub shaft 6 by running the belt 3 by the DC motor 4. It can be moved in the printing direction. A slit disk 7 is attached to the axis of the DC motor 4, and the photo sensor 8 detects the slits of the slit disk 7 and counts the number of the slits, whereby the rotation amount of the DC motor 4 can be recognized. Accordingly, it is possible to manage the position, the moving distance, and the moving speed of the carriage unit 2 that moves as the DC motor 4 rotates.

Next, a first embodiment of the present invention will be described with reference to the control block diagram of FIG. In the figure, reference numeral 30 denotes a platen gap storage unit, which stores the distance from the initial position of the platen 9 to the ribbon protector bracket 27 and the medium thickness as described with reference to FIG. The set gap and the like are stored. Reference numeral 31 denotes a platen basic movement amount storage unit. As described with reference to FIG. 2, the platen basic movement amount storage unit 31 obtains the medium thickness of the medium in advance, and according to the medium thickness, In order to provide a gap with the protector bracket 27, data indicating the amount of movement of the platen 9 according to the medium thickness is stored.

Reference numeral 32 denotes a print data analysis unit. The print data analysis unit 32 calculates the maximum number of simultaneous drive pins for each row from print data sent from the host 33. 34
a is a carriage position management control unit. The carriage position management control unit 34a determines a print speed for each line according to the number of simultaneous drive pins determined by the print data analysis unit 32.
Here, a data table for changing the moving speed of the carriage unit 2 is created.

That is, the carriage position management control unit 34
8A has data for controlling the rotation speed of the DC motor 4 for moving the carriage unit 2 described with reference to FIG. 8 according to the number of simultaneous drive pins determined by the print data analysis unit 32. When the number of simultaneously driven pins determined by the analysis unit 32 increases, data is stored that causes the rotation speed of the DC motor 4 to decrease in proportion thereto.

Reference numeral 34b denotes a pin drive time control unit which creates a data table for changing the pin drive time of the print head in accordance with the data table of the moving speed of the carriage unit 2 stored in the carriage position management control unit 34a. Have been. Reference numeral 35 denotes a carriage moving unit. The carriage moving unit 35 includes the DC motor 4, the slit disk 7, and the photo sensor 8 described with reference to FIG.

Numeral 36 denotes a platen moving section, which comprises the U / D motor 21, the slit disk 23, the photo sensor 26 and the contact detecting sensor 28 described with reference to FIG. Reference numeral 37 denotes a microprocessor which controls the above-described components, and controls the serial printer by exchanging data between the above-described units and executing arithmetic processing in the arithmetic unit 38.

Hereinafter, the operation of the first embodiment having the above-described structure will be described. First, the microprocessor 37 controls the platen moving unit 36 to perform the operation described with reference to FIG. 2 to obtain the medium thickness of the medium to be printed. Then, data of the movement amount of the platen corresponding to the medium thickness is read from the platen basic movement amount storage unit 31, and a gap corresponding to the medium thickness is set.

Next, the print data analysis unit 32 executes the host 3
The maximum number of simultaneous drive pins for each row is determined from the print data sent from the printer. Then, in order to change the printing speed for each row, here the moving speed of the carriage unit 2, according to the number of simultaneously driven pins, the carriage position management control unit 3
In step 4a, the optimum printing speed corresponding to the number of simultaneously driven pins is read for each row. That is, in a row with a small maximum number of simultaneous drive pins, data is read in which the moving speed of the carriage unit 2 is normally set. In a row with a large number of simultaneous drive pins, the moving speed of the carriage unit 2 is lower than usual. The data for lowering the rotation speed of the DC motor 4 is read out as shown in FIG. And the microprocessor 37
Controls the carriage moving unit 35 based on the printing speed of each line read by the carriage position management control unit 34a, gives the carriage unit 2 a moving speed corresponding to the number of simultaneously driven pins for each line, and controls the pin driving time. Part 3
From 4b, the pin driving time corresponding to the moving speed of the carriage unit 2, that is, data for increasing the pin driving time as the moving speed of the carriage unit 2 decreases, is read and printed.

For example, when the number of simultaneously driven pins is about the number of ANK characters, printing is executed by moving the carriage unit 2 at the highest speed given to the print head 1 and the number of simultaneously driven pins is reduced. If the number is large, printing is performed at a reduced speed accordingly. As a result, the printing speed is reduced only on the line having a large number of simultaneous drive pins, and printing is performed on the other lines without reducing the printing speed. Therefore, the printing speed is not significantly reduced as a whole.

FIG. 3 shows the print data analyzer 32.
FIG. 3 is a first control block diagram of a print data analysis unit for explaining a specific example of a method of determining the maximum number of simultaneous drive pins in FIG. 1, wherein the print data analysis unit 32 includes a character storage unit 32a and a line buffer 32b. ing. The host 33
In the print data sent from the printer, a character number is assigned to each character.

Then, characters having a large number of simultaneously driven pins are picked up in advance, classified into a plurality of types according to the number of simultaneously driven pins, and stored in the character storage section 32a. The microprocessor 37 checks the character number assigned to each character of the print data sent from the host 33 in the character storage unit 32a for each line, and classifies each character according to the number of simultaneously driven pins. Then, it is determined to which one of the groups the character belongs, and a character having the largest number of simultaneous driving pins in the line is extracted.

In the carriage position management control unit 34a, a data table for obtaining an optimum printing speed corresponding to the classification in the character storage unit 32a is created, and the extracted characters are stored in the character storage unit 32a. The printing speed of the line is determined according to the classification to which the character belongs to the latest classification. As an example, a two-stage control method will be described. As described above, a character having a large number of simultaneously driven pins is picked up and stored in the character storage unit 32a.

The microprocessor 37 determines whether to print 1
The character number assigned to each character of the line is stored in the line buffer 3
2b is temporarily stored. At this time, the character storage unit 32a
Check if the character stored in the character storage unit 32a is included in the print data for one line. Printing is performed selectively, and if there is no character stored in the character storage unit 32a in one line of print data, printing is performed at a normal printing speed.

FIG. 4 is a second control block diagram of the print data analysis unit for explaining another specific example of the method of determining the maximum number of simultaneous drive pins in the print data analysis unit 32. A print font section 32c storing a print font which is an array of dots constituting each character, a line buffer 32d temporarily storing a character number of one line to be printed, and a maximum simultaneous drive pin number. And a maximum simultaneous drive pin number storage section 32e for storing.

In the print font section 32c, the print font is a low scan type, and character fonts are stored in units of columns. FIG. 5 is a flowchart showing a method of determining the maximum number of simultaneously driven pins in the second specific example. Hereinafter, the details of the method of determining the maximum number of simultaneously driven pins will be described with reference to FIGS.

First, the microprocessor 37 clears the data stored in the maximum simultaneous drive pin storage section 32e and sets the maximum simultaneous drive pin number: A = 0 (S).
1). Next, from the print data sent from the host 33, the character number for one line is stored in the line buffer 32d.

At this time, a print font is read from the print font section 32c for each character and stored in the row buffer 32d. Here, as described above, the print font unit 32
In c, the print font is stored in units of columns,
Since data is sent from the print font unit 32c in units of columns, the microprocessor 37 recognizes the number of dots: B in each column (S2).

The maximum simultaneous drive pin number storage section 32e
Maximum number of simultaneously driven pins per row stored in A
And the dot number B of each character read from the print font unit 32c in units of columns are sequentially compared (S3). If the maximum simultaneous drive pin number A is equal to or larger than the dot number B to be printed in the comparison in S3, the maximum simultaneous drive pin number A stored in the maximum simultaneous drive pin number storage unit 32e is held as it is. When the maximum simultaneous drive pin number A is smaller than the dot number B, the dot number B is set as the maximum simultaneous drive pin number A, and the maximum simultaneous drive pin number A stored in the maximum simultaneous drive pin number storage unit 32e is used. Rewrite (S4).

The maximum number of simultaneously driven pins in each line is obtained by performing the operations from S2 to S4 on all character fonts for one line stored in the print buffer 32d (S5). For example, FIG. 6 is an explanatory diagram showing a dot configuration of the alphabet “A” as an example of a character. When the dot array of the character “A” is viewed in units of columns, the number of dots B = 3 is the largest. By executing the operations from S1 to S5 in the flowchart of FIG. 5 for the character "A", the maximum simultaneous drive pin number A = 0 is set, and then the dot number B = If there are no more than three, the maximum simultaneous drive pin number storage unit 32e
Stores the maximum number of simultaneously driven pins A = 3.

By performing the above operation for all the characters in one line, the maximum number of simultaneously driven pins in each line can be obtained. FIG. 7 is a control block diagram of a serial printer according to a second embodiment of the present invention. The platen gap storage unit 30, the platen basic movement amount storage unit 31, the print data analysis unit 32, the host 33, the carriage movement unit, and the platen movement unit 36 are the same as those in the first embodiment described with reference to FIG. Therefore, the description is omitted here.

Reference numeral 41 denotes a platen position management control unit. The platen position management control unit 41
A data table for changing the gap for each row is created according to the number of simultaneously driven pins determined in step 2. That is, when a pin (not shown) of the print head 1 is driven, a reaction force is generated which acts in a direction to increase the interval between the print head 1 and the platen 9. At this time, if the number of simultaneously driven pins is not so large, the gap between the print head 1 and the medium does not change, but if the number of simultaneously driven pins increases, the reaction force increases and the gap widens. .

For this reason, when the number of simultaneously driven pins is large, the gap is set smaller than the gap set according to the medium thickness.
The data table of the platen position management control unit 41 is configured to subtract the spread due to the reaction force from the gap set according to the medium thickness. The amount of data for forming a gap is stored according to the number of simultaneously driven pins.

Reference numeral 42 denotes a microprocessor for controlling the above-described components, and controls the serial printer by transmitting and receiving data between the above-described units and performing arithmetic processing in the arithmetic unit 38. The operation of the second embodiment having the above-described configuration will be described below. First, the microprocessor 42
Controls the platen moving unit 36 to perform the operation described with reference to FIG. 2 to obtain the medium thickness of the medium to be printed. Then, data of the movement amount of the platen corresponding to the medium thickness is read from the platen basic movement amount storage unit 31, and a gap corresponding to the medium thickness is set.

Next, the microprocessor 42 controls the print data analysis unit 32 to determine the maximum number of simultaneous drive pins for each line from the print data sent from the host 33.
In order to optimize the gap formed between the print head and the medium for each row according to the number of simultaneously driven pins, the microprocessor 42 controls the print data analysis unit 3.
The gap value corresponding to the maximum number of simultaneous drive pins for each row determined in step 2 is extracted from the platen position management control unit 41.

That is, when the number of simultaneously driven pins in a certain row is larger than the preset number, the gap is narrowed by the reaction force generated from the platen position management control unit 41 in accordance with the number of simultaneously driven pins and the gap is widened. The data indicating the amount of movement of the platen 9 is extracted as a gap value. The microprocessor 42 controls the platen moving unit 36 based on the gap value, forms a gap corresponding to the number of simultaneously driven pins for each row, and executes printing.

That is, in a row having a small number of simultaneously driven pins, printing is performed with the gap set according to the medium thickness.
For rows with a large number of simultaneous drive pins, printing is performed by narrowing the gap due to the expansion of the gap due to the reaction force.
Even if the number of simultaneously driven pins is large, the gap does not widen, and printing can always be performed with the optimum gap set according to the medium thickness.

[0049]

As described above, the present invention analyzes the maximum number of simultaneous drive pins for each line from the print data sent for printing and, for a line with a small maximum number of simultaneous drive pins, Printing is performed with the carriage moving speed set to the normal speed, and for lines with a maximum number of simultaneous drive pins, printing is performed with the carriage moving speed slower than normal, so the number of simultaneous drive pins is reduced. It is possible to prevent dot removal and print head pin breakage due to the widening of the gap due to the large number of print heads.At this time, the movement speed of the carriage is reduced only for rows with a large number of simultaneous drive pins. It has the effect of not being dropped.

Further, according to the present invention, printing is performed with the gap set according to the thickness of the medium on a line having a small maximum number of simultaneous driving pins, and on a line having a large maximum number of simultaneous driving pins. Since printing is performed with a gap smaller than usual,
In a row having a large number of simultaneous drive pins, a regular gap is obtained by widening the gap due to a large number of simultaneous drive pins, which has the effect of preventing dot removal and print head pin breakage. .

[Brief description of the drawings]

FIG. 1 is a control block diagram of a serial printer according to a first embodiment of the present invention.

FIG. 2 is a side view showing a platen up / down mechanism mounted on the serial printer.

FIG. 3 is a control block diagram for explaining a specific example of a method of determining the maximum number of simultaneously driven pins.

FIG. 4 is a control block diagram for explaining another specific example of a method of determining the maximum number of simultaneously driven pins.

FIG. 5 is a flowchart illustrating a method of determining the maximum number of simultaneously driven pins.

FIG. 6 is an explanatory diagram showing an example of a character.

FIG. 7 is a control block diagram of a serial printer according to a second embodiment of the present invention.

FIG. 8 is a perspective view illustrating a configuration of a main part of the serial printer.

FIG. 9 is a side view of the serial printer.

[Explanation of symbols]

 32 Print data analysis unit 34 Carriage position management control unit 35 Carriage movement unit 36 Platen movement unit 37 Microprocessor 41 Platen position management control unit 42 Microprocessor

Continuation of the front page (56) References JP-A-2-134253 (JP, A) JP-A-62-233256 (JP, A) JP-A-4-12869 (JP, A) JP-A-4-36861 (JP, A) JP-A-61-54958 (JP, A) JP-A-1-216853 (JP, A) JP-A-2-2018 (JP, A) JP-A-63-319164 (JP, A) 5-50638 (JP, A) JP-A 2-104238 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/30 B41J 2/36 B41J 19/18

Claims (2)

(57) [Claims] 1. A carriage on which a print head is mounted, a carriage driving means for moving the carriage, a platen opposed to the print head, and a platen moved in a direction to approach and separate from the print head. In a serial printer provided with a platen drive unit for adjusting a gap, a print data analysis unit for analyzing a maximum number of simultaneous drive pins for each line from print data sent for printing, and a carriage according to the number of simultaneous drive pins Position control means for storing the moving speed of the print head, pin driving time control means for storing the pin driving time of the print head according to the moving speed of the carriage, and the maximum number of simultaneous driving pins analyzed by the print data analyzing means. The carriage moving speed read from the carriage position management means, and And controls the carriage drive means and the pin drive time control means in accordance with the moving speed of the Yarijji, serial printer, characterized in that it comprises a control means for changing the pin drive time of the moving speed and the print head carriage. 2. A carriage on which a print head is mounted, a carriage driving means for moving the carriage, a platen opposed to the print head, and a platen moved in a direction to approach and separate from the print head. In a serial printer equipped with platen drive means for adjusting the gap, print data analysis means for analyzing the maximum number of simultaneous drive pins for each line from print data sent for printing, and a gap corresponding to the number of simultaneous drive pins A platen position management unit for storing a value, reading a gap value corresponding to the maximum number of simultaneously driven pins analyzed by the print data analysis unit from the gap position management unit, and controlling the platen drive unit based on the read gap value. And a control means for changing the gap. Nta.