JPH1044554A - Printing equipment - Google Patents

Abstract

(57) [Summary] In a printing apparatus that performs printing while moving a print head on recording paper, the adverse effect on each part of a printing mechanism when the recording paper is forcibly pulled during printing is greatly reduced. . When printing a line while loading a recording paper on a platen roller, pressing the recording paper with a paper pressing roller, and moving a thermal head in a main scanning direction by a carriage,
When one line printing is completed and the thermal head 20 is returned to the home position by the reverse movement of the carriage 33, when the platen roller 31 is rotated to perform a line feed process on the recording paper P, the recording paper P is forcibly pulled out. When such an occurrence occurs, abnormal rotation of the platen roller 31 and the paper pressing roller 35 is determined by detecting rotation of the rotating disk 36 by the optical sensor 25, and movement of the carriage 33, driving of the thermal head 20, and rotation of the platen roller 31 All operations such as driving are stopped, and the printing process is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus which performs a printing operation while moving a print head on recording paper.

[0002]

2. Description of the Related Art For example, in a laptop type word processor, a keyboard is provided at a front portion of an apparatus main body, and a display portion is provided at an openable and closable cover for covering the keyboard.
A thermal printer is built in the rear of the main unit.

This thermal printer is provided with a paper insertion port and a paper discharge port before and after the printer cover on the upper surface, and a paper transport path from the paper insertion port to a paper discharge port through a platen roller inside the thermal printer is viewed from the side. It is formed in a substantially U shape.

In printing, the paper holding roller is separated from the platen roller by a lever operation, and the leading end of the recording paper is inserted from the paper insertion opening to pass between the platen roller and the paper holding roller. The roller is returned to the original position, and the external operation knob is turned to wind the leading end of the recording paper around the platen roller, thereby setting the recording paper.

At the same time as printing, the printed portion of the recording paper is conveyed upward from the platen roller by the intermittent paper feed rotation of the platen roller, and is sequentially discharged from the discharge port to the outside of the apparatus.
The unprinted portion is sequentially conveyed from the paper insertion slot to the printer below.

On the other hand, in a thermal printer mounted on a word processor, a thermal head provided in parallel with the platen roller is operated by loading recording paper on a platen roller and performing a key operation for instructing printing.
The platen roller is pressed against the recording paper via the ink ribbon and moved in the length direction (main scanning direction) of the platen roller while thermally transferring the print data, thereby printing one line.

When one-line printing is completed, the thermal head is separated from the recording sheet and returned to the initial position (home position), and the platen roller is rotated (sub-scanning direction) to change the printing position of the recording sheet. , The printing for one line is repeated again.

[0008]

However, in a printer which performs printing while feeding the recording paper (line feed) while the recording paper is exposed to the outside as described above,
In particular, when a child uses this printer, the printer may be erroneously operated by forcibly pulling out the recording paper in the middle of printing, causing a large load on the drive mechanism including the thermal head and causing damage. There is.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a printing apparatus capable of greatly reducing adverse effects on each part of a printing mechanism when a recording sheet is forcibly pulled during printing. The purpose is to provide.

[0010]

That is, the printing apparatus according to the present invention drives the print head up and down and moves the print head in the main scanning direction while generating heat based on print data. A printing device for performing a printing operation for transporting the recording paper in the sub-scanning direction, comprising: a paper pressing member that presses the recording paper and rotates according to the transport of the recording paper; and a rotation amount of the paper pressing member. And a control unit for controlling up-drive of the print head and stopping the printing operation in accordance with information obtained from the detection unit.

That is, in the printing apparatus according to the present invention, for example, when the rotation amount of the paper pressing member is detected by the detecting means during printing in the main scanning direction by the print head, the print head is up-driven and controlled. Since the printing operation is also stopped, it is possible to urgently prevent the sequence operation of the printing mechanism from being forcibly hindered.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an electronic circuit of a word processor equipped with the printing apparatus of the present invention.

The electronic circuit of the word processor includes a control unit (CPU) 11. The control unit (CPU)
Reference numeral 11 denotes a unit for activating a system program stored in the ROM 13 in response to a key operation signal input from the key input unit 12, and controlling the operation of each circuit unit using the RAM 14 as a work memory.

The control section (CPU) 11 is connected to the liquid crystal dot matrix display section via a display control section 15 in addition to the key input section 12, the ROM 13, and the RAM 14.

The control unit (CPU) 11 is connected to a thermal print head 20 via a head driver 19, a carriage motor 18 via a carriage motor driver 17, and a line feed motor driver 23. A line feed motor 24 is connected, and a print head control / ribbon winding motor 22 is connected via a ribbon winding motor driver 21.

Further, the electronic circuit of the word processor includes an optical sensor 25 for detecting rotation of a paper press roller 35 (see FIG. 2) described later. The rotation detection signal of the paper press roller 35 output by the optical sensor 25 is supplied to the counter 26 to count the amount of rotation of the roller 35, while being directly supplied to the control unit (CPU) 11. Thus, the presence or absence of rotation of the roller 35 is determined.

The rotation amount data of the paper pressing roller 35 counted by the counter 26 is also stored in the control unit (CP
U) 11. The key input unit 12 is provided with character / symbol input keys for inputting hiragana, katakana, numbers, alphabets, symbols, and the like, and includes a kana-kanji conversion key, a line feed key, an insert key, a delete key, a print key, and the like. Various function keys, a cursor key, an execution key, and the like are provided.

In the ROM 13, a system program for controlling the entire operation of the electronic circuit of the word processor is stored in advance, and a plurality of subprograms corresponding to various functions such as creation, editing, and printing of a document are also stored in advance. Is done.

The RAM 14 stores display data to be displayed on the liquid crystal dot matrix display section 16 in addition to an input buffer and a document buffer for storing key-input character / symbol data, document data after kanji conversion, and the like. Display register, print register for storing print data to be printed out from the thermal print head 20 for each line print data corresponding to one line in the main scanning print direction, and other control registers of the control unit (CPU) 11. There is provided a work register or the like in which various input / output data are temporarily stored.

The display control unit 15 includes a common driver and a segment driver for driving a common electrode and a segment electrode of the liquid crystal dot matrix display unit 16 in accordance with display data stored in a display register in the RAM 14. It is configured in combination.

The carriage motor 18 moves the carriage 33 (see FIG. 2) on which the thermal print head 20 and the ink ribbon cassette are mounted in parallel with the surface of the platen roller 31 in the longitudinal direction of the platen roller 31 (main scanning direction). ).

The print head control / ribbon take-up motor 22 is a motor for taking up the ink ribbon mounted on the carriage 33.
It is also a motor serving as a drive source of a drive mechanism including a cam and the like for performing a switching drive between an up position where 0 is separated from the platen roller 31 and a down position pressed against the platen roller 31.

In this case, at the time of printing, when printing data is output, the cam of the drive mechanism is actuated by driving the motor 22 to move the thermal print head 20 to the down position (platen roller pressure contact position) and to wind the ink ribbon. When the printing is not performed and the print data is not output, the cam is driven by the motor 22 to move the thermal print head to the up position (platen roller separation position) and stop the winding of the ink ribbon.

The line feed motor 24 is
This is a motor that rotates the platen roller 31 to convey the recording paper P in the sub-scanning direction. For example, every time printing of one line is completed, the platen roller 31 is driven to rotate with a line feed.

FIG. 2 is a perspective view showing the structure of the printing mechanism of the word processor. Although not shown, a paper insertion port through which the recording paper P is inserted into the printer from outside the apparatus and a paper discharge port through which the printed recording paper P is sequentially discharged outside the apparatus are provided at the upper part of the printing mechanism of the word processor. And
A platen roller 31 on which the recording paper P is loaded at the time of printing is provided in the printer below the paper insertion port and the paper discharge port.

In this printer, as shown in FIG.
A transport path of the recording paper P that enters from outside the apparatus and passes through the outer periphery of the platen roller 31 of the printer to the outside of the apparatus is formed. A carriage guide 32 is provided at a position facing the surface of the platen roller 31 corresponding to the length direction of the platen roller 31 in parallel, and a carriage 33 on which the thermal print head 20 and the ink ribbon cassette are mounted is indicated by an arrow on the carriage guide 32. It is provided slidably in the direction indicated by X (main operation direction).

The carriage 33 is slid on a carriage guide 32 via a timing belt driven to rotate by the carriage motor 18. On the other hand, a paper pressing roller 35 is arranged at a position facing the surface of the platen roller 31 opposite to the carriage guide 32 and parallel to the platen roller 31.

The paper pressing roller 35 presses the recording paper P loaded on the platen roller 31 and rotates in the direction indicated by arrow B along with the rotation of the platen roller 31 in the direction indicated by arrow A. The paper press roller 35 is switched in the direction indicated by the arrow Y in response to the operation of a paper press lever (not shown), and is separated from the platen roller 31 when the recording paper P is loaded. In operation, the platen roller 31 is pressed against the platen roller 31.

A rotating disk 36 is mounted on the rotating shaft of the paper pressing roller 35, and the rotation of the rotating disk 36 is detected by the optical sensor 25. FIG. 3 is a view showing a structure for detecting the rotation of the paper pressing roller 35 by the rotating disk 36 and the optical sensor 25 in the printing mechanism of the word processor.

The paper pressing roller 35 in the printing mechanism section
Light reflection marks m are provided at regular intervals on the outer circumferential surface of the rotating disk 36 mounted coaxially with the rotating disk 36. Light emitted by the light emitting portion 25a of the optical sensor 25 The light is reflected by the light reflection mark m and received by the light receiving unit 25b.

That is, when the rotating disk 36 is also rotated as shown by the arrow B with the rotation of the paper pressing roller 35, the light sensor 25 alternately detects reflection / non-reflection of light by the light reflection mark m. The rotation of the paper pressing roller 35 is detected.

The rotation detection signal from the optical sensor 25 is counted by the counter 26, so that the rotation amount of the paper pressing roller 35 can be obtained. Note that R in the electronic circuit of the word processor (see FIG. 1)
In the AM 14, in addition to the various data buffers and data registers described above, the flag a is set to “1” while the optical sensor 25 detects the light reflection mark m of the rotating disk 36 by light detection. The rotation detection flag register in which the flag a is set to "0" in a state where the printing is not performed, the paper corresponding to the line feed distance of one line in the sub-scanning direction of the recording paper P determined according to the setting contents of the printing format. A line feed data register in which the rotation amount K of the press roller 35 is set, and the rotation amount n of the paper press roller 35 counted by the counter 26 in line feed processing for each line driven by the line feed motor 24 are set. A line feed amount register is also provided.

Next, the operation of the word processor having the above configuration will be described. FIG. 4 is a flowchart showing a printing process of the word processor. Key input unit 12
To generate document data by operating various keys of the RAM 1
In order to print this document data on the recording paper P in the state stored in the document buffer in the printer 4, first, the paper holding roller 35 is operated by operating a lever (not shown) to the platen roller 31.
From the recording paper P with respect to the platen roller 31.
Is loaded, the paper pressing roller 35 is again pressed against the platen roller 31 by operating the lever.

When the print key of the key input unit 12 is operated, the line feed motor 24 is driven by the control signal from the control unit 11, the platen roller 31 is rotated, and the transport position of the recording paper P is initially set. At the same time, the carriage motor 18 is driven to move the carriage 33 so that the thermal print head 2
The print position of 0 is initially set to the home position corresponding to the start position of one-line printing (step S
1).

Then, the character string data on the first line is read out of the document data stored in the document buffer in the RAM 14 and converted into a character pattern, and print data for one line is created and printed. (Step S2).

Here, the flag a set in the rotation detection flag register in the RAM 14 is "1" or "0".
That is, the rotational position of the rotary disk 36 coaxial with the paper feed roller 35 detected by the optical sensor 25 is
It is determined whether the vehicle stops at a position where the light reflection mark m is not detected or stops at a position where the light reflection mark m is detected (step S3).

In this step S3, if a = "0", that is, if it is determined that the paper pressing roller 35 is in a stopped state at a position where the optical sensor 25 does not detect the light reflection mark m of the rotating disk 36, for example, One line of print data written in the print register is sequentially read and output to the thermal print head 20, and at the same time, the carriage motor 18 is driven to move the thermal print head 20 in the main scanning direction. The print head control / ribbon take-up motor 22 is driven to press the thermal print head 20 down to press the recording paper P and take up the ink ribbon, thereby printing the first line of document data on the recording paper P. (Step S3 → S
4a).

When the printing process for one line on the recording paper P is started, the flag a set in the rotation detection flag register in the RAM 14 is set to "0".
Is changed from "1" to "1", that is, by detecting the light reflection mark m of the rotating disk 36 by the optical sensor 25, the paper pressing roller 35 is pulled out due to the pulling out of the recording paper P during printing or the like. It is determined whether or not it has rotated (step S5a).

Here, if the recording paper P is pulled out during the printing, the paper pressing roller 35
Is forcibly rotated, the optical sensor 25 detects the light reflection mark m of the rotating disk 36, and the flag a in the RAM 14 is set to "1", thereby detecting the forced removal of the recording paper P. Then, the drive of the print head control / ribbon take-up motor 22 is stopped, the thermal print head 22 is raised, is separated from the recording paper P, the take-up of the ink ribbon is stopped, and the carriage motor 18 is stopped. Then, the movement of the carriage 33 is stopped, and further, the driving of the thermal print head 20 is also stopped, and the printing operation is stopped (Steps S5a → S6, S5).
7).

The liquid crystal dot matrix display section 16
In response, a warning message indicating an abnormality in the printing process is displayed (step S8). On the other hand, in the step S5a, the flag a of the rotation detection flag register is not determined to be "1", that is, the flag a in which the optical sensor 25 detects the position where the light reflection mark m of the rotating disk 36 is not present. , The paper press roller 35 remains at “0”,
When the platen roller 31 and the recording paper P are in a stationary state, the one-line printing process is continued, and printing of one line of print data stored in the print register in the RAM 14 is completed. The drive of the take-up motor 22 is stopped, the thermal print head 22 is raised, is separated from the recording paper P, the winding of the ink ribbon is stopped, and the carriage motor 18 is driven in reverse to move the carriage 33 in the main scanning direction. The printing position of the thermal print head 20 on the recording paper P is returned to the home position corresponding to the start position of one-line printing (steps S5a → S10a, S1).
1a to S13a).

In steps S11a to S13a, the flag a of the rotation detection flag register is changed from "0" to "1" while the thermal print head 20 is returned to the home position due to the reverse movement of the carriage 33. If it is determined that the platen roller 31, the paper pressing roller 35, and the rotating disk 36 have been forcibly rotated by pulling out the recording paper P, the carriage motor 18 is stopped, and the thermal print head 20 is moved by the reverse movement of the carriage 33. At the same time as the return operation is stopped, the driving of the thermal print head 20 is also stopped, and the printing operation is stopped (step S12a → S7).

The liquid crystal dot matrix display section 16
In response, a warning message indicating an abnormality in the printing process is displayed (step S8). On the other hand, the step S12a
, The flag a of the rotation detection flag register is “1”
Is not determined, that is, the optical sensor 25
, The flag a of which the position where the light reflection mark m of the rotary disk 36 is not detected is detected as “0” and the paper pressing roller 3 remains
5, when the platen roller 31 and the recording paper P are stationary, the reverse movement of the carriage 33 is continued, and when it is determined that the thermal print head 20 has returned to the home position, the line feed motor 18 is driven to drive the platen. The roller 31 is rotated in the sub-scanning direction, and the printing position of the recording paper P on the thermal print head 20 is changed (step S13a → S14).

Here, with the rotation of the platen roller 31, the paper pressing roller 31 and the rotating disk 36 rotate, and the rotation amount of the paper pressing roller n detected by the optical sensor 25 and counted by the counter 26 is determined by the printing format. 1 in the sub-scanning direction of the recording paper P predetermined according to the setting contents of
When it is determined that the rotation amount K of the paper pressing roller 35 corresponding to the line feed distance for the line has been reached and the line feed processing of the recording paper P has been completed, the line feed motor 24 is stopped, and then the step S2 is performed. The process returns to the process of step 1 and the character string data of the second line is read out of the document data stored in the document buffer in the RAM 14, converted into a character pattern, and print data for one line is created. (Step S15 → S16 → S
2).

On the other hand, during the line feed processing by the rotation of the platen roller 31 while driving the line feed motor 24, the counter 26
The rotation amount of the paper press roller n corresponding to the line feed distance of one line in the sub-scanning direction of the recording paper P predetermined according to the setting content of the print format is determined by the rotation amount of the paper press roller n counted by When it is determined that the amount exceeds the amount K and the platen roller 31, the paper pressing roller 35, and the rotary disk 36 are forcibly rotated by the pulling out of the recording paper P, the driving of the line feed motor 24 is stopped and the platen roller is stopped. The rotation of the roller 31 is stopped, the line feed operation of the recording paper P is stopped, and the printing operation is stopped (step S1).
5 → S7).

The liquid crystal dot matrix display section 16
In response, a warning message indicating an abnormality in the printing process is displayed (step S8). After the printing process for one line is completed, the process returns to the step S2, and the document data stored in the document buffer in the RAM 14 is deleted from the document data.
In the state where the character string data on the line is read out and converted into a character pattern, print data for one line is created and written in the print register, a is not "0" in step S3, that is, for example, Sensor 25
When it is determined that the paper pressing roller 35 is in a stopped state at the position where the light reflection mark m of the rotating disk 36 is detected, the one line written in the print register is processed in the same manner as the printing processing of the first line. The print data is sequentially read out and output to the thermal print head 20, and at the same time, the carriage motor 18 is driven to move the thermal print head 20 in the main scanning direction. The motor 22 is driven to press the recording paper P by pressing down the thermal print head 20 and take up the ink ribbon, and the second line of the document data is printed on the recording paper P (step S3 → S).
4b).

In the state where the printing process for the second line and the first line on the recording paper P has been started, the flag a set in the rotation detection flag register in the RAM 14 becomes
Whether the change from “1” to “0”, that is, the light sensor 25 no longer detects the light reflection mark m of the rotating disk 36, and the paper holding down due to the pulling out of the recording paper P during printing or the like. It is determined whether the roller 35 has rotated (step S5b).

If the recording paper P is pulled out during the printing, the paper pressing roller 35
Is forcibly rotated, so that the light reflection mark m on the rotating disk 36 is no longer detected by the optical sensor 25 and RA
When the flag a in M14 is set to "1", the forced withdrawal of the recording paper P is detected, the drive of the print head control / ribbon winding motor 22 is stopped, and the thermal print head 22 is raised. The recording paper P is separated from the recording paper P, the winding of the ink ribbon is stopped, the carriage motor 18 is stopped, the movement of the carriage 33 is stopped, and the driving of the thermal print head 20 is also stopped, and the printing operation is stopped. Canceled (Step S5b → S
6, S7).

The liquid crystal dot matrix display section 16
In response, a warning message indicating an abnormality in the printing process is displayed (step S8). On the other hand, in step S5b, the flag a of the rotation detection flag register is not determined to be "0", that is, the flag a for which the optical sensor 25 has detected the light reflection mark m of the rotating disk 36 is "1". In the state where the paper press roller 35, platen roller 31, and recording paper P are in the stationary state, the one-line printing process is continued, and the print data for the second line and one line stored in the print register in the RAM 14 is stored. Is completed, the drive of the print head control / ribbon take-up motor 22 is stopped, the thermal print head 22 is lifted up and separated from the recording paper P, the winding of the ink ribbon is stopped, and the carriage is moved. The motor 18 is driven in the reverse direction to move the carriage 33 in the direction opposite to the main scanning direction. Print position is returned to the home position corresponding to the start position of the 1-line printing (step S5b → S10b, S11b~
S13b).

In steps S11b to S13b, the flag a of the rotation detection flag register is changed from "1" to "0" while the thermal print head 20 is returned to the home position due to the reverse movement of the carriage 33. If it is determined that the platen roller 31, the paper pressing roller 35, and the rotating disk 36 have been forcibly rotated by pulling out the recording paper P, the carriage motor 18 is stopped, and the thermal print head 20 is moved by the reverse movement of the carriage 33. At the same time as the return operation is stopped, the driving of the thermal print head 20 is also stopped, and the printing operation is stopped (step S12b → S7).

The liquid crystal dot matrix display section 16
In response, a warning message indicating an abnormality in the printing process is displayed (step S8). On the other hand, the step S12b
, The flag a of the rotation detection flag register is “0”
Is not determined, that is, the optical sensor 25
In the stationary state of the paper pressing roller 35, the platen roller 31, and the recording paper P in which the flag a in which the light reflection mark m of the rotating disk 36 is detected remains "1", the reverse movement processing of the carriage 33 is continued. When it is determined that the thermal print head 20 has returned to the home position,
The line feed motor 18 is driven to rotate the platen roller 31 in the sub-scanning direction.
The printing position of the recording paper P with respect to the line feed is changed (step S
13b → S14).

During the line feed process due to the rotation of the platen roller 31 by driving the line feed motor 24, the counter 2 is detected by the optical sensor 25.
The rotation amount of the paper pressing roller n counted by the number 6 corresponds to the line feed distance of one line in the sub-scanning direction of the recording paper P predetermined according to the setting contents of the printing format. When it is determined that the rotation amount K exceeds the rotation amount K and the platen roller 31, the paper pressing roller 35, and the rotary disk 36 are forcibly rotated by the pulling out of the recording paper P or the like, the line feed motor 24 is rotated in the same manner as described above. The driving is stopped and the rotation of the platen roller 31 is stopped,
The line feed operation of the recording paper P is stopped, and the printing operation is stopped (step S15 → S7).

The liquid crystal dot matrix display section 16
In response, a warning message indicating an abnormality in the printing process is displayed (step S8). Therefore, according to the word processor having the above configuration, the recording paper P
When printing the print data for one line while the thermal print head 20 is moved in the main scanning direction by the carriage 33, or when the printing for one line is completed, When the thermal print head 20 is returned to the home position by the reverse movement,
Further, when the platen roller 31 is rotated to perform a line feed process on the recording sheet P, if the recording sheet P is forcibly pulled out or the like, the platen roller 31 and the paper pressing roller 3
5 is abnormal rotation of the rotating disk by the optical sensor 25
6, and all operations such as movement of the carriage 33, driving of the thermal print head 20, and rotation of the platen roller 31 are stopped, and the printing process is stopped. In such a case, even if the recording paper in the middle of printing is forcibly pulled out and an erroneous operation is performed, a large load is applied to the driving mechanism of each part including the thermal print head 20 to prevent the recording paper from being damaged. be able to.

In the above embodiment, the paper pressing roller 3
The rotation state of the rotary disk 36 provided coaxially with the rotation axis of the rotary disk 5 is determined by the optical sensor 25 using the light reflection marks m provided at regular intervals on the outer peripheral surface of the rotary disk 36 as shown in FIG. For example, as shown in FIG. 5, conductive patterns d are provided at regular intervals on the outer peripheral surface of the rotary disk 36, and the conductive patterns d
A pair of electrodes 37a, 37b contacting the surface of the disk 36 provided with are provided at intervals in a direction orthogonal to the rotation direction of the disk 36, and a pair of electrodes 37a, 37b is provided between the electrodes 37a, 37b as the rotation disk 36 rotates. The control unit (CPU) 11 may detect the conduction / non-conduction of the control signal to determine the rotation state. FIG. 5 is a diagram showing a structure for detecting the rotation of the paper pressing roller 35 based on the rotating disk 36 and the electrode pattern in the printing mechanism of the word processor.

[0054]

As described above, according to the printing apparatus of the present invention, when the rotation amount of the paper holding member is detected by the detecting means during printing in the main scanning direction by the print head, for example, the print head is moved. Since the up driving is controlled and the printing operation is also stopped, it is possible to urgently prevent the sequence operation of the printing mechanism from being forcibly hindered. Therefore, it is possible to greatly reduce the adverse effect on each part of the printing mechanism when the recording paper is forcibly pulled during printing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electronic circuit of a word processor equipped with a printing apparatus of the present invention.

FIG. 2 is a perspective view showing a configuration of a printing mechanism of the word processor.

FIG. 3 is a view showing a rotation detecting structure of a paper holding roller by a rotating disk and an optical sensor in a printing mechanism of the word processor.

FIG. 4 is a flowchart showing a printing process of the word processor.

FIG. 5 is a diagram showing a rotation detection structure of a paper pressing roller based on a rotating disk and an electrode pattern in a printing mechanism of the word processor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Control part (CPU), 12 ... Key input part, 13 ... ROM, 14 ... RAM, 15 ... Display control part, 16 ... Liquid crystal dot matrix display part, 18 ... Carriage motor, 20 ... Thermal print head, 22 ... Printing Head control / ribbon winding motor, 24: line feed motor, 25: optical sensor, 25a: light emitting unit, 25b: light receiving unit, 26: counter, 31: platen roller, 32: carriage guide, 33: carriage, 34: timing Belt, 35: paper press roller, 36: rotating disk, 37a, 37b: electrode, m: light reflection mark, d: conductive pattern.

Claims (3)

[Claims] 1. A printing operation in which a print head is moved up and down and is moved in a main scanning direction while being driven to generate heat based on print data, and a recording sheet is transported in a sub scanning direction every time printing is performed in the main scanning direction. In a printing apparatus, a paper pressing member that presses the recording paper and rotates in accordance with the conveyance of the recording paper, a detecting unit that detects a rotation amount of the paper pressing member, and according to information obtained from the detecting unit Control means for controlling the up-drive of the print head and stopping the printing operation. 2. The control means controls up driving of the print head when the detection means detects a rotation amount of the paper pressing member during printing in the main scanning direction by the print head, and performs the printing operation. 2. The printing apparatus according to claim 1, wherein the control unit stops the printing. 3. The printing apparatus according to claim 1, further comprising a display unit that displays predetermined message information in accordance with an operation of the control unit.