JP3206788B2 - Impact dot printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact dot printer, and more particularly to a speed control of a print head so as not to overheat.

[0002]

2. Description of the Related Art In an impact dot printer, print data is given as the number of dots, and an ink adhering body is brought into contact with a sheet surface on a platen by a wire which is electromagnetically driven by the number of dots. Therefore, if printing is performed continuously at a high printing speed and a high printing density, the amount of power supplied to the electromagnetic drive element for driving the wire per unit time increases, and the amount of heat generated from the electromagnetic drive element increases, resulting in a print head. The temperature rises as a whole.

[0003]

When such a state of generating a large amount of heat is continued, the electromagnetic drive element for driving the wire may overheat and sometimes burn out.

The present invention has been made in consideration of the above points, and has as its object to provide an impact dot printer which performs printing so that a print head does not overheat.

[0005]

According to the present invention, there is provided an impact dot printer according to the present invention, wherein the ink-adhering member is brought into contact with a sheet mounted on a platen by a printing head opposed to the platen. In an impact dot printer in which a wire is used to apply an impact from behind the body, a temperature sensor provided in the print head, mode identification means for identifying whether a print mode is a normal mode or a copy mode, and printing to be printed. Duty count means for counting the duty per row in the data, duty limit value setting means for setting a duty limit value for one row in advance, and comparing the count value of the duty count means with the duty limit value to determine the magnitude of the duty limit value. Duty determining means for determining Temperature setting means for setting a duty limit temperature in accordance with the result of the stage identification; temperature determination means for determining whether or not the output of the temperature sensor has exceeded the duty limit temperature; Speed control means for printing the print head at a high speed when the duty count value is smaller than the duty limit value, and when the duty count value is larger than the duty limit value, when the temperature exceeds the temperature, It is characterized by having. According to the second aspect of the present invention, there is provided an impact dot printer.
In the impact dot printer according to the aspect, the temperature setting unit further sets an upper limit temperature related to a temperature rise limit of the head, and the temperature determination unit determines whether a detected temperature of the temperature sensor exceeds an upper limit temperature of the temperature setting unit. The speed control means is configured to print the print head at a low speed when the temperature detected by the temperature sensor exceeds the upper limit temperature, and to print at a high speed when the detected temperature does not exceed the upper limit temperature. It is characterized by having done. Also,
The impact dot printer according to claim 3 of the present invention is the impact dot printer according to claim 1 or 2, wherein the temperature setting means sets a temperature at which the wire sliding resistance of the print head increases as a lower limit temperature. Further set, the temperature determination means further determines whether the output of the temperature sensor has fallen below the lower limit temperature, and the speed control means has a temperature detected by the temperature sensor falls below the lower limit temperature. The print head prints at a low speed.

[0006]

According to the first aspect of the invention, the duty limit temperature is set according to the print mode. Then, the speed of the print head is determined by combining the determination result of the temperature determination unit with the determination result of the duty determination unit. That is, the duty per line in the print data to be printed counted by the duty count means by the duty determination means is compared with the duty limit value of one line by the duty limit value setting means. When the temperature determining means determines that the output of the temperature sensor has exceeded the duty limit temperature, the speed control means looks at the determination result of the duty determining means, and if the determination result is large, the printing speed is reduced. The print head is operated so as to be faster if the size is small.

According to the second aspect of the present invention, the upper limit temperature relating to the temperature rise limit of the head is set in advance by the temperature setting means. When the temperature determining means determines that the temperature of the print head detected by the temperature sensor has exceeded the upper limit temperature set by the setting means, the speed control means suspends the feed of the print head and stops sending the print head to the print head. Suppress heat generation and suppress temperature rise.

According to the third aspect of the present invention, the temperature at which the sliding resistance of the wire is significantly increased is set as the lower limit temperature by the temperature setting means. When the temperature determining means determines that the temperature detected by the temperature sensor has fallen below the lower limit temperature, the speed control means causes the print head to perform printing at a low speed, and the printing operation in a state where the sliding resistance is large causes the wire to fail. Make sure that the impact force is not weakened and the print is not light.

[0009]

According to the first aspect of the present invention, the duty limit temperature is set according to the print mode, and when the temperature of the print head reaches the duty limit temperature, the duty count value of one line in the print data is small. Prints at a high speed, and prints at a low speed when the print speed is large. Therefore, it is possible to suppress a rise in the temperature of the print head and prevent overheating and burning. When the temperature does not reach the duty limit temperature, printing is performed at a high speed without looking at the duty of one line, so that the printing process is performed in the shortest time and the throughput of the printer can be increased. Furthermore, since the duty limit temperature is set to a different value depending on the printing mode of the printer, that is, the normal mode or the copy mode,
Maximize printer throughput.
In this regard, the same effect can be obtained even if the duty limit value for one line is changed according to the print mode.

According to the second aspect of the present invention, when the temperature of the print head exceeds a preset upper limit temperature, the feed of the print head is stopped and the power supply to the print head is stopped.
The temperature rise of the print head can be suppressed, and overheating damage of the print head can be prevented. In addition, since the printing speed is determined while observing the temperature of the print head, the throughput of the printer can be maximized, and the burning of the print head due to the variation in the temperature rise characteristics of each print head can be prevented. Can be.

According to the third aspect of the present invention, when the temperature of the print head is lowered to a lower limit temperature at which the sliding resistance of the wire is significantly increased, the speed of the print head is reduced to sufficiently apply the impact force of the wire. Can be done. As a result,
It is possible to prevent printing from becoming thin even at low temperatures.

[0012]

FIG. 1 shows a control circuit of an impact dot printer according to the present invention. According to the present invention, the output obtained by comparing the print head temperature t detected by the temperature detecting element T provided in the print head of the impact dot printer with the set temperatures TC, TH and TD by the temperature determining means TCM is speed controlled. Means given to the SCM. Speed control means S
The duty determination result from the duty determination means DCM is also given to the CM. The duty determining means DCM
The determination is made by comparing the duty count value d in the print data detected by the duty counter with the duty set value D from the duty setting means.

The speed control means SCM forms a control signal in consideration of the result of the duty determination by the duty determination means DCM, and outputs this control signal to the motor P for driving the print head.
M. Set temperature TC, TH, TD
And the duty set value D is set by the setting command means SDM in accordance with the result of the mode identification means MDM identifying the print mode.
Is set. Here, the set temperature TC is the lower limit temperature at which the sliding resistance of the wire of the print head increases, the set temperature TH is the upper limit temperature at which the print head is overheated, and the set temperature TD is one line printing in the print data. This is the duty limit temperature determined by the duty. Thereby, the print head is fed at a high speed, for example, full speed or a low speed, for example, half speed.

The operation of this circuit will be described later with reference to the flowchart of FIG. 5 and the printing speed characteristic diagram of FIG.

FIG. 2 is a vertical sectional view of an impact dot printer according to the present invention, in which a box-shaped lower case 101 and an upper case 102 are combined. A first printer cover 110 and a second printer cover 120 that can be opened and closed are combined with the upper case 102 and can be opened when inspecting the inside of the printer. In this printer, a paper P is inserted from a paper feed port 103 and drawn inside by a tractor 130, and a platen 140 and a print head 150
Is set to a position between

The print head 150 is mounted on a carriage 153 supported by carriage guide shafts 151 and 152, and an ink ribbon cartridge 154 is provided on the side of the print head 150 opposite the platen. The printed paper P is delivered to the delivery roller 160 and the delivery unit 16.
1 and is pushed out onto the sheet guide 170 and sent out from the paper discharge port 181 in the paper discharge direction A.

FIG. 3 is a perspective view of the impact dot printer according to the present invention, and FIG. 2 shows a state where the impact dot printer is cut along the line XX in FIG. In FIG. 3, a lower case 101 and an upper case 102 combined on the lower case 101 are provided. A first printer cover 110 and a second printer cover 120 are combined with the upper case 102. The sheet guide 170 is shown to be continuous from the lower part of the second printer cover 120.

FIG. 4 shows the print head 150 shown in FIG. 2 as a cross section slightly obliquely upward from the right in the figure. As shown in this FIG.
The nose 2 protrudes rightward from the nose, and the wire 3 is protruded from the tip of the nose 2 toward the platen 140 to strike the sheet P together with the ink ribbon IR onto the platen 140.

The wire 3 has its base end fixed to the armature 4 in the main body 1, and its tip and center are guided by a wire tip guide 5 and a wire intermediate guide 6, respectively. The armature 4 constitutes an electromagnetic driving element by the core 7 and the coil 8 wound around the core 7, and the electromagnetic driving element generates an electromagnetic driving force to operate the wire 3. A board 10 is mounted on the nose side of the core 7 with an insulating plate 9 interposed therebetween.
Is provided with a thermistor T for detecting the temperature of the core 7. Further, a damper 16 is provided behind the armature 4 between the armature 4 and the main body 1, and supports the armature 4.

FIG. 5 is a flowchart showing the control contents of the impact dot printer. This control operation will be described in comparison with the block diagram shown in FIG. First, the printing mode identification means MDM identifies the printing mode shown in step S1. Print mode is 1 for platen
Normal mode in which a sheet of paper is set and printing is performed;
There is a copy mode in which more than one sheet of paper and carbon paper are set and copying is performed. The latter requires a higher impact force than the former, so that a large current is applied to the electromagnetic drive element, which generates more heat in the print head. Therefore, the print head duty limit temperature T
D differs depending on the print mode.

In accordance with the print mode identified in step S1, the setting command means SDM gives commands in step S2 to the setting means for setting various set values, ie, the set temperatures TC, TH and TD, and the setting means for setting the duty set value D. Accordingly, the set temperatures TC, TH, TD and the duty set value D
Is given to the temperature determination means TCM and the head speed control means SCM.

Next, in step S3, the temperature t of the print head is detected by a temperature sensor such as a thermistor T. The detected temperature t is sequentially compared with each set temperature TC, TH, TD by the temperature sensor TCM. First, a comparison is made in step S4 with a lower limit temperature TC which is a temperature at which the sliding resistance of the wire in the print head increases. This is intended to prevent the printing on the paper from being thinned due to the fact that the wire is not fed at the correct strength at a low temperature. When the detected temperature t is lower than the lower limit temperature TC,
In step S11, the speed control means SCM causes the print head to run at half speed.

When the detected temperature t is equal to or higher than the lower limit temperature TC,
Proceeding to step S5, the temperature is compared with the upper limit temperature TH which is the temperature rise limit temperature of the print head. At this time, if the detected temperature t is equal to or higher than the upper limit temperature TH, a pause state is set in step S6, and the temperature determination unit TCM does not give an output to the speed control unit SCM. Then, the process returns to step S2.

If the detected temperature t is lower than the upper limit temperature TH, the process proceeds to step S7, and it is determined whether the detected temperature t is lower than the duty limit temperature TD. If the duty per line included in the print data is low, the duty limit temperature TD is to allow the print head to print at a high speed on the assumption that there is room for temperature rise, and the full speed printing is set in step S10.

On the other hand, if the detected temperature t is already higher than the set temperature TD, the duty counter d counts the duty count value d in step S8, and proceeds to step S9 where the speed control means SCM sets the duty set value by the duty setting means D. Compared with D, if the duty count value d is low, the full speed printing setting in step S10 is performed, and if the duty count value d is high, the half speed printing setting in step S11 is performed. Based on this setting, the speed control means SCM drives the motor PM to print one line in step S12. Motor PM
The use of a pulse motor facilitates speed control.

FIG. 6 shows how the temperature of the print head rises due to the difference in the print mode of the printer. Here, there are a normal mode and a copy mode. In the normal mode, the temperature rise is slower than in the copy mode. In both modes, the temperature rises quickly in the full speed range and is gentle in the half speed range. Therefore, the above-mentioned set temperature is determined in consideration of this temperature rise characteristic. That is, it is necessary to lower the set temperature in the copy mode.
In the normal mode, the set temperature can be set higher. Therefore, the duty limit temperature TD is about 50 ° C. in the normal mode, but is about 40 ° C. in the copy mode. In this case, the upper limit temperature TH is 1 in any mode.
00 ° C. The lower limit temperature TC is about 10 ° C.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control circuit of an impact dot printer according to the present invention.

FIG. 2 is a longitudinal sectional view of an impact dot printer to be controlled by the present invention.

FIG. 3 is a perspective view of an impact dot printer to be controlled by the present invention.

FIG. 4 is a diagram showing the print head 150 in FIG. 2 as a cross section from a slightly obliquely upper right direction in the figure.

FIG. 5 is a flowchart showing an example of control contents of the impact dot printer according to the present invention.

FIG. 6 is a characteristic diagram showing how the temperature of a print head rises due to a difference in a print mode of the printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Nose 3 Wire 4 Armature 5 Wire tip guide 6 Wire intermediate guide 7 Core 8 Coil 9 Insulating plate 10 Substrate 101 Lower case 102 Upper case 103 Paper discharge port 110 First printer cover 120 Second printer cover 130 Tractor 140 Platen 150 Print head 151 Carriage guide shaft 152 Carriage guide shaft 153 Carriage 154 Ink ribbon cartridge 160 Discharge roller 161 Discharge unit 170 Sheet guide 181 Discharge port

──────────────────────────────────────────────────続 き Continuing on the front page (72) Minoru Tanaka 3-5-5 Yamato, Suwa City, Nagano Prefecture Inside Seiko Epson Corporation (72) Kazuhiko Yamamoto 3rd-3rd Yamato, Suwa City, Nagano Prefecture No. 5 Inside Seiko Epson Corporation (56) References JP-A-2-55150 (JP, A) JP-A-1-151364 (JP, A) JP-A-7-61001 (JP, A) JP-A-1 -308647 (JP, A) JP-A-3-61547 (JP, A) JP-A-3-248886 (JP, A) JP-A-2-81643 (JP, A) (58) Fields investigated (Int. Cl) . ^7, DB name) B41J 2/30

Claims (3)

(57) [Claims] An impact dot printer configured to apply a wire impact to a sheet mounted on a platen from behind the ink-adhering body by a print head arranged opposite to the platen. A temperature sensor provided in the print head, mode identification means for identifying whether a print mode is a normal mode or a copy mode, duty count means for counting a duty per line in print data to be printed, Duty limit value setting means for setting a duty limit value for one row; Duty determination means for comparing the count value of the duty count means with the duty limit value to determine the magnitude thereof; and according to the identification result of the mode identification means. Temperature setting means for setting the duty limit temperature by using Temperature determination means for determining whether or not the output of the temperature sensor has exceeded the duty limit temperature; and when the temperature detected by the temperature sensor has exceeded the duty limit temperature, the duty is determined by checking the determination result of the duty determination means. An impact dot printer, comprising: speed control means for causing the print head to print at a high speed when the count value is smaller than the duty limit value, and at a low speed when the count value is larger than the duty limit value. 2. The temperature setting means further sets an upper limit temperature relating to a temperature rise limit of the head, and the temperature determination means determines whether a temperature detected by the temperature sensor exceeds an upper limit temperature of the temperature setting means. Wherein the speed control means prints the print head at a low speed when the temperature detected by the temperature sensor exceeds the upper limit temperature, and prints at a high speed when the temperature does not exceed the upper limit temperature. The impact dot printer according to claim 1. 3. The temperature setting means further sets a temperature at which the wire sliding resistance of the print head increases as a lower limit temperature, and the temperature determination means sets an output of the temperature sensor below the lower limit temperature. The speed control means, when the temperature detected by the temperature sensor is lower than the lower limit temperature, causes the print head to print at a lower speed. The impact dot printer according to claim 1.