JP2003231319A - Ink jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet printer for printing by transmitting the rotating force of a carriage (recording head) driving motor to a belt through a pulley and reciprocating a carriage secured to the belt every time when a line is printed, wherein the machine is not shut down even if a slip takes place between the belt and the pulley. <P>SOLUTION: In the ink jet printer for forming an image by ejecting ink drops from a recording head, when a slip takes place between a carriage driving pulley and a carriage driving belt during print operation, a shift caused by the slip is detected automatically and the positional information of the carriage outputted from an encoder coupled directly with a carriage driving motor is corrected by the positional information of the carriage outputted from the linear encoder thereof, and then print operation is resumed based on the correction results. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer which forms an image by ejecting ink droplets from a recording head onto a recording medium which moves in a fixed direction, and particularly to a carriage control position by a drive motor and an actual carriage. The present invention relates to an inkjet printer that automatically corrects the amount of deviation when a deviation occurs at the position due to slippage of the driving means.

[0002]

2. Description of the Related Art FIG. 1 is a perspective view showing a conventional ink jet printer.

A method that has been conventionally adopted will be described below. In the configuration of the conventional inkjet printer 1, a carriage 2 is provided with a recording head, and further, the carriage 2 is provided with ink reservoirs 3 and 3A for supplying ink to the recording head. Connected with.

The carriage 2 is reciprocally moved in the main scanning direction indicated by an arrow X in the drawing by a carriage driving mechanism 6.
The carriage driving mechanism 6 includes a motor 6a, a pulley 6b, a belt 6c, and a guide member 6d. The carriage 2 is fixed to the belt 6c, and the motor 6a drives the belt 6 to rotate.
It is reciprocally moved to the arrow X via c.

Reference numeral 8 denotes a recording medium conveying mechanism, which conveys the recording medium P in the sub-scanning direction indicated by an arrow Y in the drawing, and a conveyance motor 8
a, a pair of transport rollers 8b and a pair of transport rollers 8c.

The recording medium P is sent out from a sheet feeding mechanism (not shown) and is nipped by the conveying rollers 8b.

The transport roller 8c is driven by the transport motor 8a at a constant speed, and is driven by an interlocking mechanism (not shown) so that the transport roller 8c rotates at an extremely slightly higher peripheral speed than the transport roller 8b. Is transported without causing slack.

Further, the recording medium P has its inclination and the like corrected by a paper feed guide (not shown), and is sandwiched by the conveying rollers 8c and passes through the recording section.

In this way, while moving the recording medium P in the sub-scanning direction at a constant speed, the carriage 2 is moved in the main scanning direction at a constant speed so that the ink ejected from the recording head adheres to the recording medium P for a predetermined amount. Some had recorded images in the range.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet printer which forms a good image on a recording medium and does not stop due to an abnormal alarm.
Conventionally, the carriage 2 on which the ink reservoirs 3 and 3A are mounted in FIG.
Although the belt 6c is reciprocally moved in the main scanning direction indicated by the arrow X in the figure, the belt 6c is endless and flat in order to prevent displacement of the ink ejection position due to stretching of the belt and drive unevenness due to a timing belt or the like. A metal belt is used.

However, the carriage 2 on which the ink reservoirs 3 and 3A are mounted has a large mass, and when the movement acceleration of the carriage is increased in order to improve the productivity as a printer, the inertia of the carriage or the like causes the inertia between the belt 6c and the pulley 6b. There is a tendency that slippage occurs and the rotation amount of the motor 6a cannot be accurately transmitted to the carriage 2.

When such a slip is detected, conventionally, the machine is stopped and an abnormal alarm is issued to the operator.

Therefore, there is a drawback that the operating rate of the printer is reduced. The present invention has been made in view of such problems. That is, when a character or an image is formed on a recording medium by ink droplets ejected from the recording head according to the movement of the carriage, a deviation occurs between the control position of the carriage by the drive motor and the actual position of the carriage due to the slip of the driving means or the like. It is an object of the present invention to provide an ink jet printer that does not stop an abnormal alarm by detecting a deviation amount and automatically correcting it.

[0014]

The above object of the present invention is achieved by the following components. That is, according to claim 1,
An ink jet printer that forms an image by ejecting ink droplets on a moving recording medium in a direction perpendicular to the moving direction of the recording medium, and a carriage having the recording head and driving the carriage. Motor, an encoder disk provided with a plurality of radial scales for measuring the amount of rotation of the motor fixedly mounted on the motor shaft, and fixed to the machine body so that the radial scales can be detected. A motor rotation amount detection means having a detection sensor for detecting the radial scale, a power transmission means for converting the rotation of the motor into a movement operation of the carriage, and a plurality of equalizers for measuring the movement amount of the carriage. A linear encoder plate, which has a scale and is arranged parallel to the moving position of the carriage on the machine body, can detect the uniform scale. Characterized in that it comprises a carriage movement detector and a fixed detector head to said carriage so.

According to a third aspect of the present invention, in an ink jet printer for forming an image on a moving recording medium by ejecting ink droplets from a recording head while moving in a direction perpendicular to the moving direction of the recording medium. A carriage having a recording head, a motor for driving the carriage, an encoder disk provided with a plurality of radial scales for measuring a rotation amount of a motor fixedly arranged on a motor shaft, and the radial disk. A motor rotation amount detection means fixed to the machine body so as to detect a scale and having a detection sensor for detecting the radial scale, a power transmission means for converting rotation of the motor into a movement operation of the carriage, and a carriage. A linear encoder provided with a plurality of uniform scales for measuring the movement amount of the carriage and arranged parallel to the movement position of the carriage on the machine body. Control for controlling a motor for driving the carriage via the power transmission means, the carriage movement amount detection means having a double plate and a detection head fixed to the carriage so as to detect the uniform scale. The control means calculates the output of the motor rotation amount detection means and converts it into the carriage position information a, and calculates the output of the carriage movement amount detection means and converts into the carriage position information b, By correcting the position information a of the carriage so as to match the position information b of the carriage, the deviation of the movement amount of the carriage with respect to the rotation amount of the motor by the power transmission means is corrected.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto.

FIG. 2 is a perspective view showing the structure of the ink jet printer of the present invention. In FIG. 2, P is a recording medium (hereinafter, the recording medium is simply referred to as recording paper), on which characters or images are formed.

Reference numerals 101 and 103 denote conveyance rollers. The conveyance rollers 101 and 103 hold the recording paper P and convey the recording paper P. Therefore, the conveyance rollers 101 and 103 rotate to the ink jet printer 100 via the shafts 102 and 104. Arranged freely (not shown).

A pair of shafts 102 of a pair of conveying rollers 101
One of them is provided with a conveying motor M, which is a driving unit, directly or via a decelerating unit (not shown) so as to rotate the conveying roller 101 to feed and convey the recording paper P.

Reference numeral 108 denotes a carriage, which has a recording head on which an ink reservoir 108a is placed, and a large number of ejection ports (not shown) for ejecting ink droplets are arranged in parallel in the Y direction on the surface facing the recording paper P. is doing.

The carriage 108 is slidably provided on the guide member 109 so that the carriage 108 can move in a direction perpendicular to the paper feeding direction of the recording paper P (X direction in the drawing).
It is fixed to a part of an endless belt 111 suspended between a pulley 112 and a pulley 113.

The motor M1 is connected to the pulley 112 directly or via a reduction means (not shown), and the belt 11
Drive 1

The pair of guide members 109 are the carriage 108.
The carriage 1 is fixed at the same distance as the guide member through holes and fixed to the inkjet printer (not shown).
08 is moved while being accurately guided in parallel with the recording paper P which faces it.

Reference numeral 120 denotes a linear encoder plate, which is made of transparent glass, a PET plate, or the like, and has a scale 120a for measuring the movement amount and the movement direction of the carriage 108 in the X direction.
The dots are evenly applied in the direction at a density of about 360 dpi (dot per inch, but 1 inch is 2.54 cm).

Reference numeral 121 denotes a detection head, which is the carriage 108.
The scale 120a of the linear encoder plate 120 is detected while moving with the carriage, and its output is input to the control means C and used for controlling ejection of ink droplets during main scanning.

The linear encoder plate 120 and the detection head 121 constitute a carriage movement amount detecting means.

Here, the linear encoder plate and its detection head may be those of the above-mentioned transmission type optical system, reflection type optical system, or those utilizing magnetism.

Reference numeral 130 denotes an encoder disk, which is made of a transparent glass plate or the like, and is provided with graduations 130a for measuring the rotation amount and the rotation direction of the motor M1 radially and evenly.

A detection sensor 131 is fixed to the ink jet printer 100, detects the scale 130a of the encoder disk 130, and its output is input to the control means C.
It is used for carriage position control in the main scanning direction and motor PID control (acceleration / deceleration control, speed control).

The encoder disk 130 and the detection sensor 131 constitute a motor rotation amount detecting means.

Reference numeral 140 denotes an HP sensor, which is the carriage 108.
Is located at the home position at the right end in the figure, the carriage 108 is detected and its output is output to the control means C.

The operation of the ink jet printer will be outlined below. For example, the control unit C conveys the recording paper P fed from the paper feed cassette (not shown) to the conveyance rollers 103 and 101 by the control normally performed by the ink jet printer, and forms an image on the recording head. Stop at the correct position.

Thereafter, the carry amount of the recording paper P is calculated from the output of the recording paper carry amount detection sensor (not shown), and the carry motor M is rotated to carry the carry roller 101 and the carry roller 10.
The recording paper P nipped by 3 is moved by a predetermined line width in the Y direction in the figure.

That is, the sub-scan is performed. Then, the pulley 112 and the belt 111 connected to the motor M1 are driven by the rotation of the motor M1 directly or via a decelerating means (not shown), and the carriage 108 fixed to the belt 111 is rotated in the positive and negative directions of the motor M1 by the guide member 109. And is moved in the X direction (left and right).

That is, main scanning is performed. Here, the + -in the X direction illustrated corresponds to the + -in the X direction in the description of FIG. 3 described later.

Here, it is possible to raise the apparent resolution of the scale 130a of the encoder disk 130 to a level equal to or higher than that of the scale 120a of the linear encoder plate through the multiplication means.

The control means C is the encoder disk 13
0 and a motor rotation amount detection means including a detection sensor 131 calculates the movement amount of the carriage 108 from the paper edge and the conveyance amount of the recording paper P from the paper edge detection sensor output (not shown). A corresponding image signal is read according to the movement amount information and the conveyance amount information of the recording paper P, and ink droplets are ejected from the ejection port at a position corresponding to the image signal,
An image is formed on the recording paper P.

As described above, a predetermined image is formed at a predetermined position on the recording paper by repeating the sub-scanning and the main scanning, and the recording paper P on which the image is formed is discharged to the outside by a discharge roller (not shown). Paper is transported.

Now, the method of measuring the position information of the carriage by the control means C will be described in detail.

C is a control means, which is a scale 1 of the linear encoder plate 120 from the detection head 121 via the input means C1.
20a detection output (pulse), detection sensor 131 (described later) detection output of encoder disk 130 scale 130a (pulse), HP sensor 140 carriage detection output (1/0), and capping sensor 150 cap detection output. (1/0) is input and the result of arithmetic processing according to the control program stored in the storage means (not shown) stored in advance is output via the output means C2 to rotate the motor M1.

Specifically, the scale 130 of the encoder disk 130 for measuring the rotation amount and rotation direction of the motor M1.
a is a phase A (not shown) disposed in the detection sensor 131.
Detected by the B-phase sensor, the A-phase
Processing for detecting the rotation amount and rotation direction of the motor M1 by the B-phase sensor is performed, and the carriage position information a obtained by converting the actual accumulated rotation amount of the motor M1 into the movement amount of the carriage is constantly calculated. The value of the carriage position information a at the time of the origin return operation is set to 0 and the value of the carriage position information a is rewritten.

Similarly, the scales 120a of the linear encoder plate 120 for measuring the movement amount and the movement direction of the carriage 108 in the X direction are arranged in the detection head 121 and are not shown in the A and B phases. A process for detecting the movement amount and the movement direction of the linear encoder plate by the A phase and the B phase which is usually performed by the control means C is detected by the sensor, and the actual accumulated movement amount of the carriage 108 is converted into the movement amount of the carriage. The position information a of the carriage is constantly calculated, and the value of the position information b of the carriage at the time of returning to the origin described later when the power is turned on is set to 0 and the value of the position information b of the carriage is rewritten.

Here, the above-mentioned "processing for detecting the moving amount and moving direction of the linear encoder plate by the A phase / B phase which is normally performed" means an A phase sensor and a B phase sensor whose encoder scales are out of phase. The rotation direction or the moving direction is detected by detecting and detecting whether the B-phase sensor output rises or falls while the A-phase sensor output is ON, and counts the number of rising and falling edge detections of the A-phase and B-phase sensor outputs. By doing so, the amount of rotation or the amount of movement simply added in both the positive and negative directions is measured (for example, when the original A-phase / B-phase output signal has a resolution equivalent to 180 dpi, it is possible to obtain a signal equivalent to 720 dpi by quadrupling).
Then, the actual cumulative rotation amount or movement amount can be calculated by performing addition or subtraction based on the rotation direction or movement direction such as addition in the positive direction and subtraction in the negative direction with respect to the simply added rotation amount or movement amount. To tell.

An example of the origin return operation when the power is turned on will be described below with reference to FIGS. 3 and 2.

FIG. 3 is a conceptual diagram of the origin returning operation of the carriage when the power is turned on. The control means C detects the power-on,
When the output of the HP sensor 140 is checked and the carriage is detected, in FIG. 3A, the rotation amount of the motor M1 corresponding to the moving distance (for example, 150 mm) of the carriage 108 is expressed by the number of output pulses converted into the scale 130a. Calculate

Then, the motor M is moved so that the carriage 108 is out of the carriage detection range of the HP sensor 140.
1 is rotated at a medium speed so as to move in the + X direction, the number of output pulses of the scale 130a is counted by the detection sensor 131, and when the number of pulses of the calculation result of the term is reached, the motor M1
To stop.

Then, the motor M1 is connected to the carriage 108.
Is rotated at a low speed so as to move in the -X direction, and is stopped when the HP sensor 140 detects the carriage 108.

This completes the return-to-origin operation of the carriage 108, and simultaneously sets the carriage position information a and the carriage position information b to "0".

When the power is turned on, the output of the capping sensor 150 is checked, and when the carriage 108 is detected, the cap lock release solenoid (also used as the cutter solenoid) is activated in FIG. 3B, After removing the capping lock (not shown), the motor M1 is rotated at a low speed so that the carriage 108 moves in the −X direction, and is stopped when the HP sensor 140 detects the carriage 108.

This completes the return-to-origin operation of the carriage 108, and simultaneously sets the carriage position information a and the carriage position information b to "0".

After the origin return operation is completed, the carriage position information a and the carriage position information b are constantly calculated and always grasped with the origin return operation completion time being 0.

When the above-mentioned origin return operation is performed,
For example, if the HP sensor cannot detect the carriage 108 within 28 seconds, a warning is output to the operator as a time-out error and the machine is stopped.

FIG. 4 is a conceptual diagram of the origin correction operation of the present invention. The origin correction operation when the carriage position information a and the carriage position information b deviate from each other by a prescribed value 1 or more during printing according to the present invention will be described below with reference to FIGS. 4 and 2.

The control means C compares the carriage position information "a" with the carriage position information "b" during printing, and when the deviation between the two becomes larger than a predetermined value 1, which is set in advance, the pulley 112
It is determined that slippage has occurred between the belt 111 and the belt 111, the information on the current printing state is temporarily stored in the storage unit, and the following origin correction operation is performed.

First, the control means C determines, for example, 10 mm before the origin of the carriage based on the current carriage position information a1.
Scale 13 of encoder disk 130 corresponding to the distance to
The pulse number x of 0a is calculated.

Then, the carriage 108 is located at the position 1 before the origin.
The motor M1 is rotated in the -X direction at a higher speed than the middle speed of the home-return operation when the power is turned on so as to reach 0 mm.
The number of output pulses of the detection sensor 131 is counted, and when the number of pulses x of the calculation result of the term is reached, the motor M1 is stopped.

In order to read the position information of the linear encoder plate, after stopping for a predetermined time to stabilize the operation of the servo,
Alternatively, for example, the scale 130a is checked by the detection sensor 131 and stopped until it is determined that the servo operation is stable by detecting that the rotation direction of the motor M1 has stopped changing within a short time, and the current carriage is stopped. Based on the distance from the position to the origin, in other words, the value of the current carriage position information b, the pulse number y of the scale 120a corresponding to the current carriage position information b2 to the origin is calculated, and then the scale equivalent to the pulse number y. The number of pulses α equivalent to 130a is calculated.

Then, the motor M1 is connected to the carriage 108.
Is rotated at a low speed so that moves further in the -X direction, and scale 1
The pulse number of 30a is counted, and when the pulse number α is reached, the motor M1 is stopped, and at the same time, the current carriage position information a3 of the motor rotation amount detection means is matched with the current carriage position information b3 (0) of the carriage position detection means. Complete the origin correction.

Then, before the origin correction operation is started, the temporarily stored information regarding the printing is read, and the printing is newly started with the corrected position information.

Further, during printing, the carriage position information of the motor rotation amount detecting means and the carriage position information of the carriage position detecting means are constantly compared, and the difference (deviation) between the position information values of both is more than the previously measured difference. When the difference is equal to or more than the predetermined value 2, it is determined that the carriage 108 has collided, an abnormal alarm is output to the operator, and the inkjet printer is abnormally stopped.

[0061]

As described above, in an ink jet printer which forms an image by ejecting ink droplets from a recording head onto a recording paper which moves in a fixed direction, slippage occurs between a carriage driving pulley and a carriage driving belt. In this case, by automatically correcting the carriage position information by the encoder output directly connected to the carriage drive motor with the carriage position information by the linear encoder output of the carriage, high-quality print position deviation in the main scanning direction does not occur. An image can be obtained and the machine operation rate can be improved because the machine is not stopped.

[Brief description of drawings]

FIG. 1 is a perspective view showing a conventionally used inkjet printer.

FIG. 2 is a perspective view showing the configuration of the inkjet printer of the present invention.

FIG. 3 is a conceptual diagram of an origin returning operation of the carriage when the power is turned on.

FIG. 4 is a conceptual diagram of an origin correction operation of the present invention.

[Explanation of symbols]

1,100 inkjet printer 2,108 carriage 3, 3A, 108a ink reservoir 8a, M transport motor 8c, 8b, 101, 103 Conveying rollers C control means C1 input means C2 output means P recording medium (recording paper) 6a, M1 motor 130 encoder disk 131 detection sensor 6b, 112, 113 pulleys 6c, 111 belt 6d, 109 guide member 120 linear encoder plate 121 Detection head 140 HP sensor

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2C056 EA21 EB11 EB29 EB36 EC11                       EC34 EC77 FA10 HA38 HA52                 2C480 CA01 CA16 CA31 CA32 CA44                       CB34 CB35 DA01 EC10

Claims (4)

[Claims] 1. An inkjet printer for forming an image on a moving recording medium by ejecting ink droplets from the recording head while moving in a direction perpendicular to the moving direction of the recording medium, and a carriage having the recording head. , A motor for driving the carriage, an encoder disk provided with a plurality of radial scales for measuring the rotation amount of a motor fixedly arranged on the motor shaft, and the radial scale so that the radial scale can be detected. Motor rotation amount detection means fixed to a machine body and having a detection sensor for detecting the radial scale, power transmission means for converting rotation of the motor into movement movement of the carriage, and movement amount of the carriage are measured. A linear encoder plate provided with a plurality of uniform scales for parallel to the moving position of the carriage in the machine body, and the uniform scales. An ink jet printer, comprising: a carriage movement amount detection unit having a detection head fixed to the carriage so as to detect a ridge. 2. The power transmission means for converting the rotation of the motor into the reciprocating movement of the carriage is suspended between the drive pulley connected to the motor and the drive pulley and the driven pulley, and the carriage is partially attached to the drive pulley. A fixed endless belt, and a carriage guide member fixed to the main body through the carriage so that the carriage can move in parallel with the recording medium and the linear encoder plate. The inkjet printer according to claim 1, wherein the inkjet printer is configured so that the carriage can be moved left and right by rotating the motor in positive and negative directions. 3. An inkjet printer for forming an image on a moving recording medium by ejecting ink droplets from the recording head while moving in a direction perpendicular to the moving direction of the recording medium, and a carriage having the recording head. , A motor for driving the carriage, an encoder disk provided with a plurality of radial scales for measuring the rotation amount of a motor fixedly arranged on the motor shaft, and the radial scale so that the radial scale can be detected. Motor rotation amount detection means fixed to a machine body and having a detection sensor for detecting the radial scale, power transmission means for converting rotation of the motor into movement movement of the carriage, and movement amount of the carriage are measured. A linear encoder plate provided with a plurality of uniform scales for parallel to the moving position of the carriage in the machine body, and the uniform scales. A carriage movement amount detection means having a detection head fixed to the carriage so as to detect swell, and a control means for controlling a motor for driving the carriage via the power transmission means,
The control means calculates the output of the motor rotation amount detecting means and converts it into the carriage position information a, and calculates the output of the carriage movement amount detecting means to calculate the carriage position information b.
By correcting the carriage position information a so as to match the carriage position information b, it is possible to correct the deviation of the movement amount of the carriage with respect to the rotation amount of the motor by the power transmission means. Characteristic inkjet printer. 4. The misalignment correction is performed by always comparing the position information a of the carriage with the position information b of the carriage at the start of motor driving, and interrupting the printing when the position information values of both are different by a predetermined value or more. Then, based on the position information a of the carriage, the carriage is moved at a high speed to a predetermined position before the origin, and at the predetermined position, the position information b of the carriage is moved.
The distance to the origin is calculated based on the calculation result, the calculation result is further converted into the rotation amount of the motor rotation amount detecting means, the carriage is moved at a low speed based on the value of the conversion result, and the carriage is stopped. 4. The inkjet printer according to claim 3, wherein the position information a of the carriage is corrected so as to match, and printing is restarted based on the corrected position information b of the carriage and the position information a of the carriage.