JP2010132417A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a carrying failure of continuous paper without newly arranging a jam detecting mechanism. <P>SOLUTION: This printer has a printing head in a carriage, and prints while reciprocating its carriage in the substantially orthogonal direction to the paper sending direction, and has a concentration detecting part arranged in the carriage and detecting the concentration of a character printed on the paper, and a processing part for detecting the carrying failure of the paper by monitoring the output of the concentration detecting part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing apparatus that prints continuous paper, and more particularly, to a printing apparatus that detects a conveyance failure of continuous paper.

  A printing apparatus such as a serial impact dot matrix printer known as a conventional wire dot printer, when printing on continuous printing paper (hereinafter referred to as “continuous paper”), is a sprocket for printing paper on a tractor that transports the paper. Unlike paper that is transported with holes aligned and cut to a predetermined size such as A4 size, the user can set the printing paper once on the tractor and print continuously until the printing paper runs out It can be done.

  In such a printing apparatus, a printing paper conveyance failure may occur for some reason. Therefore, the roller is moved by linking to the paper conveyance mechanism of the tractor unit, and the passage of the roller is detected by a transmission sensor or the like. A jam detection mechanism for detecting that the printing paper has fallen into a poorly transported state, such as a means for detecting the transport state of the paper or a means for detecting the transport state of the paper by detecting the passage of sprocket holes in the continuous paper. I have to prepare.

On the other hand, in a printing apparatus that prints on paper that has been cut to a predetermined size, a paper width sensor for detecting the paper width is used to detect that the end of the print paper does not reach a predetermined position, and In some cases, it is detected that the printing paper has fallen into a poorly conveyed state (see, for example, Patent Document 1).
JP-A-5-58012 (paragraphs “0017” to “0024”, FIGS. 1 and 2)

As described above, a printing apparatus having a jam detection mechanism can detect a conveyance failure of printing paper, but there are many low-priced printing apparatuses with an emphasis on cost that do not have a jam detection mechanism. To do.
However, in the above-described conventional technique, when a printing paper conveyance failure occurs in a printing apparatus that does not include a jam detection mechanism, printing paper that cannot be sent because printing is continued in a printing paper conveyance failure state. In this case, the printing paper is torn and printed directly on the platen, leading to pin breakage of the print head and damage to the platen. For this reason, there is a problem that it is necessary to detect that the printing paper is in a poorly conveyed state, and in this case, it is necessary to provide a jam detection mechanism.

  Further, as described in Patent Document 1 described above, the paper width sensor is used to detect that the end of the printing paper does not reach a predetermined position without providing a jam detection mechanism, and for each printing paper. When detecting that the printing paper is in a poorly transported state, there is a problem in that it is not possible to detect a transport failure of continuous paper even though it can detect a transport failure of paper cut to a predetermined size. is there.

  An object of the present invention is to solve such a problem, and an object of the present invention is to detect a conveyance failure of a continuous sheet without newly providing a jam detection mechanism.

  Therefore, the present invention provides a printing apparatus having a print head on a carriage and performing printing while reciprocating the carriage in a direction substantially orthogonal to the paper feed direction, and is arranged on the carriage and printed on paper. A density detection unit that detects the density of the characters and a processing unit that monitors the output of the density detection unit and detects a paper conveyance failure.

  According to the present invention thus configured, it is possible to detect a continuous paper conveyance failure without newly providing a jam detection mechanism.

  Hereinafter, embodiments of a printing apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a main part plan view showing the configuration of the printing apparatus in the first embodiment, and FIG. 2 is a side sectional view showing the configuration of the printing apparatus in the first embodiment.
1 and 2, a printing apparatus 100 is a printer that prints continuous paper 1.
The tractor 2 is provided with a pin protruding outside a belt that is rotated by driving means such as a motor (not shown), and a sprocket hole provided on both sides of the continuous paper 1 is fitted to the pin. The tractor 2 is configured to be rotated by driving means such as a conveyance motor (not shown), and can feed the continuous paper 1 by rotating.

The platen 3 receives the impact of the wire pin provided by the print head 7 and is configured to rotate together with the tractor 2 by a driving means such as a conveyance motor (not shown), and conveys the continuous paper 1 fed by the tractor 2. To do.
The paper end sensor 4 is provided between the tractor 2 and the platen 3, and is a sensor for detecting the presence or absence of the preceding continuous paper 1 in which the conveyed continuous paper 1 enters the platen 3. In this embodiment, the paper end sensor 4 is provided with a detection lever for detecting the continuous paper 1, and the presence or absence of the continuous paper 1 is detected by blocking the optical axis of the light transmission type sensor by the lever. Shall.

  As shown in FIG. 1, the carriage 6 penetrates the carriage shaft 10 and is configured to be slidable in a direction substantially perpendicular to the direction in which the continuous paper 1 is conveyed (the direction indicated by the arrow A in FIG. 1). Yes. The carriage 6 has a print head 7 that protrudes a wire pin and abuts the ink ribbon 11 on the continuous paper 1, and light reflection that irradiates the continuous paper 1 near the print head 7 and inputs the reflected light. A carriage sensor 8 as a mold sensor and a ribbon protector 9 for guiding the ink ribbon 11 are provided. Therefore, printing can be performed on the continuous paper 1 by reciprocating the carriage 6 in a direction substantially orthogonal to the direction in which the continuous paper 1 is conveyed.

  The pull-up roller assembly 13 is disposed above the carriage 6 and includes a pull-up roller 14 that pulls up the continuous paper 1. The pull-up roller assembly 13 is pulled up by the pull-up roller 14 that is rotationally driven by driving means such as a conveyance motor (not shown). 2 is guided and conveyed to the sheet stage 15 disposed in the upper part of the apparatus (in the direction indicated by the arrow B in FIG. 2).

FIG. 3 is a block diagram showing the configuration of the printing apparatus in the first embodiment.
In FIG. 3, the host apparatus 20 is a host computer that outputs print data that instructs the printing apparatus 100 to perform printing.
The printing apparatus 100 includes a data reception unit 21, a data analysis unit 22, a print data generation output unit 23, an operation panel unit 24, a display unit 25, a space control unit 26, a paper transport control unit 28, a paper detection circuit unit 30, and a storage unit. 31 and a main control unit 32 for controlling them.

The data receiving unit 21 receives print data from the host device 20, and the data analyzing unit 22 analyzes the print data received by the data receiving unit 21. The print data generation / output unit 23 generates print data expanded into bitmap data based on the result analyzed by the data analysis unit 22 and prints it on the continuous paper 1 by the print head 7 based on the print data.
The operation panel unit 24 receives an operator's operation through an input unit such as an operation button, and the display unit 25 is a lamp, a display, or the like that displays the status of the printing apparatus 100.

  The space control unit 26 rotationally drives the space motor 27 and drives a belt connected to the space motor 27 to slide the carriage 6 in a direction substantially perpendicular to the direction in which the continuous paper 1 is conveyed. . Therefore, the space control unit 26 can reciprocate the print head 7 and the carriage sensor 8 provided on the carriage 6 in the width direction substantially orthogonal to the conveyance direction of the continuous paper 1 by driving the space motor 27. It is like that.

The sheet conveyance control unit 28 rotates the tractor 2 and the platen 3 by rotating the conveyance motor 29 to perform feeding operations such as feeding, discharging, and line feed of the continuous sheet 1.
The paper detection circuit unit 30 constitutes a non-reflective part detection unit as a density detection unit with the carriage sensor 8 and receives the reflected light of the light emitted toward the continuous paper 1 to reflect the light (light: white part). Alternatively, a non-reflective state (dark: black part) is detected.

This paper detection circuit unit 30 can detect the reflected or non-reflected state by receiving the reflected light of the light emitted toward the continuous paper 1, and can detect the paper width of the continuous paper 1. It is possible to detect the shading of the characters printed on 1.
For example, as shown in FIG. 4, the paper detection circuit unit 30 is configured such that the emitter outputs of the light emitting diode LED1, the light receiving transistor TR1, and the light receiving transistor TR1 as the carriage sensor 8 to which the resistors R1 and R2 are connected are output from the comparator Q1. On the other hand, a voltage obtained by dividing 5V by resistors R4 and R5 is connected to the “+” terminal as a slice level. The output of the comparator Q1 is pulled up by a resistor R3 and is connected to the input port of the main controller 32.

The storage unit 31 is configured by a memory that stores a control program for controlling the entire printing apparatus 100, a state of the apparatus, and the like.
The main control unit 32 is configured by a CPU or the like as a calculation unit and a control unit, controls the entire printing apparatus 100 based on a control program stored in the storage unit 31, and based on print data received from the host apparatus 20. The carriage 6 is moved line by line, and printing is performed on the continuous paper 1 by the print head 7.

The operation of the above-described configuration will be described in accordance with the step represented by S in the flowchart showing the printing operation in the first embodiment of FIG.
First, the operation before entering the printing operation will be described.
When the continuous paper 1 is not set in the printing apparatus 100, the user sets the continuous paper 1 by aligning the sprocket holes of the continuous paper 1 and the pins of the tractor 2. After the continuous paper 1 is set on the tractor 2, when the data receiving unit 21 of the printing apparatus 100 receives print data from the host apparatus 20 or receives a paper feed command from the operation panel unit 24 that accepts a user operation, the paper is conveyed. The control unit 28 drives the transport motor 29 to rotate the tractor 2 and the platen 3 through the gears, and performs a paper feeding operation for transporting the continuous paper 1 between the platen 3 and the carriage 6.

Next, the space control unit 26 drives the space motor 27 to detect the width of the continuous paper 1 and performs a spacing operation for sliding the carriage 6, and moves the movable range of the carriage 6 to move the carriage sensor. 8, the edge position of the continuous paper 1, that is, the paper width of the continuous paper 1 is detected, and the detected paper width is stored in the storage unit 31 as paper width information.
Note that the operation for detecting the width of the continuous paper 1 is performed when the continuous paper 1 is fed and when the printer 100 is turned on.

  S1: When the data receiving unit 21 of the printing apparatus 100 receives print data from the host apparatus 20 after the operation of detecting the width of the continuous sheet 1 is completed, the space control unit 26 and the print data generation output are based on the received print data. The unit 23 starts the spacing operation of the carriage 6 and the printing operation that impacts the pins of the print head 7 on the continuous paper 1 via the ink ribbon 11 to perform the printing operation for one line (row).

S2: In the spacing operation of the carriage 6, the output of the paper detection circuit 30 as the output of the carriage sensor 8 provided in the carriage 6 is input to the input port of the main control unit 32, and the main control unit 32 receives the input carriage. During the spacing operation on the continuous paper 1 based on the output of the sensor 8, it is possible to determine the presence or absence of a black portion that is a non-reflective portion.
Here, when printing one line of print data, since the line to be printed has not been printed yet, the output of the carriage sensor 8 indicates the reflection state until the carriage sensor 8 exceeds the end of the continuous paper 1. . For this reason, when the print range by the print data does not protrude from the continuous paper 1, the black portion is not detected, and the process proceeds to S3 (S2: NO).

S3: The space control unit 26 ends the spacing operation and ends the one-line printing operation.
S4: When the printing of one line is completed, the paper conveyance control unit 28 drives the tractor 2 and the platen 3 based on the print data, and performs a line feed operation for conveying the necessary amount of continuous paper 1.
As described above, the printing operation is normally performed by repeating the operations of S1 to S4.

On the other hand, in S2, when a non-reflective part is detected (S2: YES), the process proceeds to S5.
S5: Even when the non-reflective portion is detected in S2, if the range of the spacing operation exceeds the end of the continuous paper 1 such as printing near the end of the continuous paper 1, the carriage sensor 8 1, the carriage sensor 8 detects the non-reflective state by the platen 3, and its output indicates the non-reflective state. Therefore, the main control unit 32 determines whether the carriage sensor 8 has detected a non-reflective state beyond the end of the continuous paper 1 based on the paper width information stored in the storage unit 31.

The main control unit 32 compares the amount of movement by the spacing operation of the carriage 6 with the sheet width information stored in the storage unit 31. If the main control unit 32 determines that the carriage 6 exceeds the width of the continuous sheet 1, the process proceeds to S6. If it is determined that the width of the continuous paper 1 is not exceeded (YES), the process proceeds to S7 (NO).
S6: If it is determined that the carriage 6 has exceeded the width of the continuous paper 1, if the printing operation is continued, the main control section 32 directly prints on the position where the continuous paper 1 does not exist, that is, directly on the platen 3. If there is remaining print data on the same line, a process for discarding the print data is performed, the process proceeds to S3, and the printing operation for one line is finished.

In this way, the printing apparatus 100 performs a one-line printing operation. However, if the jammed state where the conveyance of the continuous paper 1 becomes impossible for some reason, the continuous paper 1 is conveyed even if the tractor 2 and the platen 3 are rotated. I can't do it.
For example, as shown in FIG. 6, when the printed continuous paper 1 continues to hang over the back of the printing apparatus 100 beyond the sheet stage 15, printing is performed depending on the position where the fed continuous paper 1 is disposed. When the continuous paper 1 is placed on the continuous paper 1 to be fed, the load increases and the continuous paper 1 to be fed cannot be pulled up.

  When such a state is reached, the tractor 2 rotates to convey the continuous paper 1 but the continuous paper 1 cannot be pulled up, causing hole galling and the tractor 2 cannot carry the continuous paper 1. Further, since the platen 3 rotates in the same manner, the platen 3 has a slight conveyance force, but, like the pull-up roller 14, there is no feed force to pull up the continuous paper 1 with an increased load. 1 slips.

In this way, when the continuous paper 1 comes off from the tractor 2 and slips, the paper end sensor 4 arranged at the front stage of the platen 3 still detects the presence of the paper, and as shown in FIG. Will continue to print near the same line.
If the paper end sensor 4 detects the presence of paper while the continuous paper 1 is in a poor transport state as in the above example, the continuous paper 1 moves even if the continuous paper 1 is transported in S4. Instead, when the printing operation for the next line is started, the portion where the overprinting is performed in S2 is detected as a black portion which is a non-reflective portion.

Here, a process for detecting the jam state of the continuous paper 1 based on an example of the output of the carriage sensor 8 when the printing operation is continued in the state of the conveyance failure of the continuous paper 1 shown in FIG. 7 will be described.
When the normal continuous paper 1 is transported, the output of the carriage sensor 8 indicates a reflection state because the printing operation is performed on a line (white portion) where printing is not performed. When bidirectional printing is performed by the carriage 6 that reciprocates, the character immediately after printing is read by the carriage sensor 8, so that the forward direction in which an unprinted area can be detected (the direction indicated by the arrow C in FIG. 1). ) The non-reflective portion is detected only during the spacing operation. In addition, a slice level is set in the paper detection circuit 30, and when the slice level is exceeded, the output of the comparator Q1 becomes “H” indicating a non-reflective state.

However, when the conveyance failure of the continuous paper 1 occurs, the line feed operation is not performed and the printing is repeated in the vicinity of the same line so that a printing state as shown in FIG. 7 is obtained.
At this time, the output level of the carriage sensor 8 is lower than the reference voltage of the comparator Q1 at the portion where the repeated printing is frequently performed due to the conveyance failure of the continuous paper 1 (black portion), and the comparator Q1 of the paper detection circuit unit 30 is not. “H” indicating the reflection state is output.

  The main control unit 32 as a processing unit for detecting a conveyance failure of the continuous paper 1 detects a position where the output signal of the paper detection circuit unit 30 changes from “L” indicating the reflection state to “H” indicating the non-reflection state. Then, the position is calculated from the amount of movement of the carriage 6, and the calculated position information is compared with the paper width information stored in the storage unit 31, so that the reflection state is “L” and the non-reflection state is “H”. It is determined whether or not the position to be changed is within the range of the width of the continuous paper 1, that is, whether or not the overprinting has been performed.

Returning to the explanation of FIG.
S5: When it is determined that the position where the reflection state changes from “L” to “H” indicating the non-reflection state is within the width of the continuous paper 1, that is, the overprinting is performed, It is determined that the conveyance failure of the continuous paper 1 has occurred, and the process proceeds to S7 (NO).
S7: The space control unit 26 stops the spacing operation and stops the impact operation of the print head 7.

S8: The main control unit 32 displays on the display unit 25 an alarm to the effect that the continuous paper 1 has jammed.
In this way, the carriage sensor 8 and the paper detection circuit unit 30 and the main control unit 32 as a processing unit for detecting the conveyance failure of the continuous paper 1 can detect the conveyance failure of the continuous paper 1.

  As described above, in the first embodiment, a non-reflective portion as a black portion is detected using an existing paper width detection sensor without providing a jam detection mechanism in a tractor or the like. It is possible to detect a conveyance failure of continuous paper, and when a conveyance failure of continuous paper occurs during the printing operation of a large amount of print data, the printing operation can be stopped by detecting the conveyance failure. Is obtained.

  Further, it is possible to prevent the platen and the head pin from being damaged due to the direct printing on the platen caused by the conveyance failure of the continuous paper.

In the configuration of the second embodiment, a width counter, a black counter, and an LF counter are provided in the storage unit in the configuration of the first embodiment. The configuration of the second embodiment will be described based on the block diagram showing the configuration of the printing apparatus in the second embodiment of FIG. Note that parts similar to those of the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.
8, the printing apparatus 100 includes a data receiving unit 21, a data analysis unit 22, a print data generation output unit 23, an operation panel unit 24, a display unit 25, a space control unit 26, as in the configuration of the first embodiment. The sheet conveyance control unit 28, the sheet detection circuit unit 30, the storage unit 31, and the main control unit 32 that controls them are configured.

  The space control unit 26 rotationally drives the space motor 27 and drives a belt connected to the space motor 27 to slide the carriage 6 in a direction substantially perpendicular to the direction in which the continuous paper 1 is conveyed. . Therefore, the space control unit 26 can reciprocate the print head 7 and the carriage sensor 8 provided on the carriage 6 in the width direction substantially orthogonal to the conveyance direction of the continuous paper 1 by driving the space motor 27. It is like that.

Further, the space control unit 26 sequentially switches the excitation phase and rotationally drives the space motor 27 to perform a spacing operation. The main control unit 32 also switches the sheet by the carriage sensor 8 at the switching timing of the excitation phase of the space motor 27. The output signal of the detection circuit 30 can be read.
The sheet conveyance control unit 28 rotates the tractor 2 and the platen 3 by rotating the conveyance motor 29 to perform sheet feeding, discharging, and feeding operations of the continuous sheet 1.

The configuration of the paper detection circuit unit 30 that receives the reflected light of the light emitted toward the continuous paper 1 by the carriage sensor 8 and detects the reflection state or the non-reflection state, that is, white or black, is the first embodiment. This is the same as the configuration shown in FIG.
The storage unit 31 is composed of a control program for controlling the entire printing apparatus 100 and a memory for storing the state of the apparatus, etc., as in the first embodiment, but in the second embodiment, the width is limited. A counter 311, a black counter 312, and an LF counter 313 are also provided.

The width counter 311 stores the number of times the output signal of the paper detection circuit 30 continues as “H” indicating a non-reflective state (black portion) at the switching timing of the excitation phase of the space motor 27 in the spacing operation.
The main control unit 32 reads the output signal of the comparator Q1 of the paper detection circuit 30 by the carriage sensor 8 at the timing when the space control unit 26 performs the excitation phase switching process of the space motor 27 as shown in FIG. The number of times that the signal continues as “H” indicating a non-reflective state (black portion) is stored in the width counter 311.

  FIG. 9 shows the timing at which the main controller 32 reads the output signal of the comparator Q1 of the paper detection circuit 30 by the carriage sensor 8, and reads the output signal of the comparator Q1 of the paper detection circuit 30 every time the excitation phase is switched. For example, in FIG. 9, black is detected by reading the output signal of the comparator Q1 at the nth time, n + 2th time, and n + 4th time. This indicates that no black is detected.

The black counter 312 stores whether or not it has been detected that the number of times stored in the width counter 311 has exceeded the threshold value X within the spacing operation of one line.
When the main control unit 32 reads the output signal of the comparator Q1 of the “H” paper detection circuit 30 indicating the non-reflective state (black portion), the main control unit 32 compares the number of times stored in the width counter 311 with the threshold value X to determine the width. When it is determined that the counter 311 exceeds the threshold value X, the fact that the width counter 311 exceeds the threshold value X is stored in the black counter 312.

The LF counter 313 stores the number of continuous lines (the number of lines) that has detected that the number of times stored in the width counter 311 has exceeded the threshold value X.
The main control unit 32 stores, in the LF counter 313, the number of continuous lines of the black counter 312 in which the width counter 311 has exceeded the threshold value X when the spacing operation for one line is completed. When it is detected that the number of stored lines exceeds the threshold value Y, it is determined that overprinting has been performed, and it is determined that a conveyance failure of the continuous paper 1 has occurred.

The operation of the above-described configuration will be described in accordance with steps represented by S in the flowchart showing the printing operation in the second embodiment of FIG.
Since the paper feeding operation before entering the printing operation is the same as that of the first embodiment, the description thereof is omitted, and the operation after the continuous paper 1 is fed, the width of the continuous paper 1 is detected, and the print data is received. Will be explained.

When the printing apparatus 100 is turned on, the main control unit 32 stores the width counter 311 of the storage unit 31 in “0” and the black counter 312 in the width counter 311 within the “0: 1 line spacing operation”. , The LF counter 313 is initialized to “0”.
S21: The main control unit 32 initializes the width counter 311 to “0” for each printing operation of one line.

S22: Based on the print data received from the host device 20, the space control unit 26 and the print data generation output unit 23 impact the spacing operation of the carriage 6 and the pins of the print head 7 on the continuous paper 1 via the ink ribbon 11. The space control unit 26 performs the excitation phase switching process of the space motor 27.
S23: The main control unit 32 reads the output of the paper detection circuit 30 as the output of the carriage sensor 8 provided in the carriage 6 in synchronization with the timing of the excitation phase switching process performed by the space control unit 26.

S24: The main control unit 32 can determine the presence or absence of a black portion which is a non-reflective portion while performing a spacing operation on the continuous paper 1 based on the input output of the carriage sensor 8. Note that the main control unit 32 as the jam detecting means determines the presence / absence of the black part which is a non-reflective part as in the first embodiment.
If a non-reflective part (black part) is not detected (NO), the process proceeds to S29. If a non-reflective part (black part) is detected (YES), the process proceeds to S25.

S25: When the non-reflecting part (black part) is detected, the main control part 32 adds “1” to the width counter 311.
S26: When “1” is added to the width counter 311, the main control unit 32 determines whether or not the width counter 311 has exceeded the threshold value X. If it is determined that the threshold has been exceeded (YES), the process proceeds to S27. When it determines with not exceeding (NO), a process is transfered to S30.

S27: When the width counter 311 determines that the threshold value X has exceeded the threshold value X, the main control unit 32 determines that the carriage sensor 8 exceeds the end (printing area) of the continuous paper 1 based on the paper width information stored in the storage unit 31. It is determined whether or not a reflection state is detected.
The main control unit 32 compares the amount of movement by the spacing operation of the carriage 6 with the sheet width information stored in the storage unit 31. If the main control unit 32 determines that the carriage 6 exceeds the width of the continuous sheet 1, the process proceeds to S29. (NO), if it is determined that the width of the continuous paper 1 is not exceeded, the process proceeds to S28 (YES).

  S28: The output of the sheet detection circuit 30 as the output of the carriage sensor 8 is repeatedly read at every timing of the excitation phase switching process performed by the space control unit 26, and the black portion whose width counter 311 exceeds the threshold value X is detected in the print area. The detected main control unit 32 stores “1” in the black counter 312, and stores in the storage unit 31 that a non-reflective state (black portion) is detected in the print area of the continuous paper 1 during the one-line printing operation. Store and move the process to S30.

S29: When the non-reflecting part (black part) is not detected in S24 (S24: NO), the main control part 32 initializes the width counter 311 to “0”. Thus, when the non-reflecting part (black part) is not continuously detected, the width of the non-reflecting part (black part) to be detected can be changed by the threshold value X by initializing the width counter 311.
Even when it is determined in S27 that the carriage 6 has exceeded the width of the continuous paper 1, the main control unit 32 initializes the width counter 311 to “0”.

S30: The space control unit 26 repeats the processes of S2 to S29 until the spacing operation for driving the one-line space motor is completed (NO), and when the one-line spacing operation is completed, the process proceeds to S31 ( YES).
S31: When the one-line spacing operation is completed, the main control unit 32 determines whether or not a non-reflective state (black portion) is detected in the printing area of the continuous paper 1 during the one-line printing operation, that is, the black counter 312. Is determined to be “1”, and the non-reflective state (black portion) is detected (the black counter 312 is “1”), the process proceeds to S32, and the non-reflective state (black portion) is determined. If it is determined that it is not detected (the black counter 312 is “0”), the process proceeds to S34.

S32: If it is determined that the non-reflective state (black portion) is detected (the black counter 312 is “1”), the main control unit 32 adds “1” to the LF counter 313.
S33: Also, the main control unit 32 initializes the black counter 312 to “0”, and proceeds to S35.
S34: If it is determined in S31 that the non-reflective state (black portion) is not detected (the black counter 312 is “0”), the main control unit 32 initializes the LF counter 313 to “0”, and the process proceeds to S35. To do.

S35: The main control unit 32 determines whether or not print data for the next line exists. If it is determined that the print data is present, the process proceeds to S36, and if it is determined that there is no print data, the print operation is terminated.
S36: If it is determined that the print data for the next line exists, the main control unit 32 determines whether or not the line in which the non-reflective state (black portion) is continuously detected exceeds the threshold Y, that is, the LF counter 313 sets the threshold Y. It is determined whether or not it has exceeded, and if it is determined that it has exceeded, the process proceeds to S38. On the other hand, if it is determined that it does not exceed, the process proceeds to S37.

S37: If it is determined that the line in which the non-reflective state (black portion) is continuously detected does not exceed the threshold value Y, the paper transport control unit 28 drives the tractor 2 and the platen 3 based on the print data, and the continuous paper 1 A line feed operation for conveying the required amount is performed, the process proceeds to S21, and a printing operation for the next line is performed.
S38: If it is determined that the line in which the non-reflective state (black portion) is continuously detected exceeds the threshold value Y, the main control unit 32 recognizes that the black portion due to overprinting exists and prints the remaining print data. Is stopped, and an alarm indicating that a jam of the continuous paper 1 has occurred is displayed on the display unit 25.

In this way, the processing from S31 to S36 is performed, and it is determined that the line (row) in which the non-reflective state (black portion) by the overlapping printing is detected is continuous, and the detected number of lines exceeds the threshold Y, and the continuous paper 1 is detected.
It should be noted that when the threshold Y is set to “0” and there is even one line (row) in which a non-reflective state (black portion) is detected by overlapping printing, the occurrence of a conveyance failure of the continuous paper 1 may be detected. Good.

  In this embodiment, for example, when printing is performed on the preformat continuous paper 1 on which ruled lines are printed in advance as shown in FIG. 11, when the carriage 6 passes through the black ruled line portion 110a in the normal state 111, the width counter 311 Although the black portion is detected and increased at each excitation phase switching timing, if the width of the ruled line portion 110a, that is, the width counter 311 does not reach the threshold value X, the black counter 312 does not store the detected black portion. Therefore, erroneous detection of a conveyance failure of the continuous paper 1 does not occur.

Further, even when a black portion is detected by the ruled line portion 110b in the horizontal direction (the spacing operation direction of the carriage 6), if the number of lines in which the black portion is continuously detected does not exceed the threshold Y, the conveyance failure of the continuous paper 1 The line feed operation for initializing the LF counter 313 and transporting the continuous paper 1 is performed without determining that the occurrence of the error.
However, in the jam state 112, the overprinting progresses and the black portion is enlarged, so that the width counter 311 exceeds the threshold value X, and the black counter 312 stores that the black portion is detected ("1"), and the LF The counter 313 also increases for each line feed, and when the threshold value Y is exceeded, a conveyance failure of the continuous paper 1 can be detected.

In this way, the main control unit 32 reads the output of the paper detection circuit 30 as the output of the carriage sensor 8 at every timing of the excitation phase switching process of the space motor 27, and based on the output, the width, location, By detecting the frequency, it is possible to prevent erroneous detection of a conveyance failure of the continuous paper 1 due to the ruled lines of the preformat continuous paper 1.
As described above, in the second embodiment, in addition to the effects of the first embodiment, the output of the carriage sensor as the paper width detection sensor is read at every excitation phase switching timing of the space motor, and based on the output. By detecting the width of the black portion and the number of continuous lines where the black portion exists, it is possible to prevent erroneous detection of continuous paper conveyance failure due to the ruled lines of the preformat continuous paper. Is obtained.

  In the first embodiment and the second embodiment, the printing apparatus provided with means for detecting continuous paper conveyance failure has been described as a general-purpose printer. However, the printing apparatus is not limited to this, and a horizontal printer is cut. A printer that prints on paper or an inkjet printer may be used.

The principal part top view which shows the structure of the printing apparatus in 1st Example. Side sectional view showing the configuration of the printing apparatus according to the first embodiment. 1 is a block diagram illustrating a configuration of a printing apparatus according to a first embodiment. Explanatory drawing which shows the structure of the paper detection circuit in a 1st Example. Flowchart showing the printing operation in the first embodiment Explanatory drawing of the cause of paper conveyance failure in the first embodiment Explanatory drawing of the output signal of the paper detection circuit in the first embodiment The block diagram which shows the structure of the printing apparatus in 2nd Example. Time chart showing sensor lead timing in the second embodiment Flowchart showing the printing operation in the second embodiment. Explanatory drawing of the output signal of the paper detection circuit in the second embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Continuous paper 2 Tractor 3 Platen 4 Paper end sensor 5 Sheet guide 6 Carriage 7 Print head 8 Carriage sensor 9 Ribbon protector 10 Carriage shaft 11 Ink ribbon 13 Pull-up roller assembly 14 Pull-up roller 15 Sheet stage 100 Printing device

Claims (7)

In a printing apparatus having a print head in a carriage and performing printing while reciprocating the carriage in a direction substantially perpendicular to the paper feed direction,
A density detector arranged on the carriage for detecting the density of characters printed on paper;
A printing apparatus comprising: a processing unit that monitors an output of the density detection unit and detects a paper conveyance failure. The printing apparatus according to claim 1.
The printing apparatus according to claim 1, wherein when the dark portion is detected based on an output of the darkness detection unit, the processing unit determines that the paper is poorly conveyed. The printing apparatus according to claim 2.
A storage unit is provided for storing the number of times the dark part is detected based on the output of the density detection unit,
The processing unit reads the output of the density detection unit every time the excitation phase of the motor that moves the carriage is switched, and stores the number of times that the dark part is detected on the sheet based on the output in the storage unit. A printing apparatus characterized by determining that the paper is poorly conveyed when the value exceeds the value. The printing apparatus according to claim 2.
A storage unit is provided for storing the number of times that a dark part is detected based on the output of the density detection unit and the number of rows in which the number of times exceeds a first threshold,
The processing unit reads the output of the concentration detection unit every time the excitation phase of the motor that moves the carriage is switched, and stores the number of times that the dark portion is detected based on the output in the storage unit, for each line feed operation. The number of lines in which the number of times stored in the storage unit exceeds a first threshold value is stored in the storage unit, and when the number of lines exceeds a second threshold value, it is determined that the sheet conveyance is defective. Printing device. The printing apparatus according to claim 4.
The printing apparatus according to claim 1, wherein the number of times of storage in the storage unit is the number of times that a dark portion is detected continuously based on an output of the density detection unit. The printing apparatus according to claim 4 or 5,
The printing apparatus according to claim 1, wherein the number of rows stored in the storage unit is the number of rows in which a dark portion is continuously detected based on an output of the density detection unit. The printing apparatus according to any one of claims 1 to 6,
The printing apparatus according to claim 1, wherein the density detection unit is a sensor that receives reflected light of light emitted toward a sheet and detects a reflection state or a non-reflection state to detect a sheet width of the sheet.

Images