JPH06134981A - Recorder - Google Patents

Abstract

PURPOSE:To decrease recording noises and to improve the recording speed and character quality by providing means, which individually detect the attachments and removals of a plurality of recording heads, and means, which control a driving signal to a driving source for a carriage in response to the outputs of the above described means. CONSTITUTION:Detecting switches 3h-1 and 3h-2, which individually detect the presence or absence of the mounting of each ink head, are provided at ink-head mounting parts 3i-1 and 3i-2 of a carriage 3. When one ink head is mounted on the carriage 3, the pulse width of a driving signal is set in short width by the amount corresponding to the reduction in inertial load of the carriage 3. In an accelerating region (a), the pulse width of phi1-phi4 are set 5t 4t 3t 2t. In a constant speed region (b), the pulse width are set at 2t. In the decelerating region (c), the pulse widths are set 2t 3t 4t 5t. In this way excitation is performed. Thus, each conducting width is shortened by 1t, and the rotating torque of a step motor 13 is decreased. The transient characteristic of the running of the carriage is made to be the same as the characteristic when the carriages 3 are two. In this way, the printing noises are decreased, and the printing speed and the quality of the recorded characters are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus, and more particularly to a recording apparatus which reciprocates a carriage having a plurality of recording heads detachably mounted on a recording medium to perform recording.

[0002]

2. Description of the Related Art In recent years, as computerized office equipment has become widespread, the operating noise generated by a recording device built into a recording type calculator or the like becomes noise, and not only for users but also for non-users. It is a cause of reduced efficiency. For this reason, there is an increasing demand for noise reduction of equipment, and it is desired to reduce noise of the recording apparatus.

Recently, however, a recording apparatus that employs an ink jet system that produces a quiet operation sound has appeared. In this type of recording apparatus, ink is supplied to a recording head having a fine orifice (or nozzle), an energy generator provided in this orifice is driven based on print data, and kinetic force is applied to the ink in the orifice. There is an on-demand type recording device that ejects ink droplets from the tip of an orifice and lands them on a recording medium to record characters and symbols. This recording apparatus can be configured as a non-impact type quiet recording apparatus unlike a recording apparatus that uses an ink supply source such as an ink ribbon or an ink roller.

In this recording apparatus, a recording head integrally formed with an ink tank which is an ink supply source is detachably mounted on a carriage, and is moved in a direction orthogonal to a recording medium conveyance direction by a power source such as a step motor. The method of recording is adopted.

On the other hand, in response to the demand for diversification and efficiency of office work, the function of the printing apparatus has been improved from monochromatic printing to multicolor printing of two or more colors.

[0006]

However, in a recording apparatus in which a plurality of ink source-integrated recording heads (hereinafter referred to as ink heads) having different ink colors are mounted as described above, the user mounts them on the carriage. When the number of ink heads to be changed is changed, the load on the step motor, which is the drive source of the carriage, especially the inertial load changes, causing the dot pitch irregularity in the characters of the dot matrix configuration of the liquid droplets, and Cause decline.

Further, in the operation of the motor in the constant speed printing traveling section of the carriage and the acceleration and deceleration traveling sections sandwiching the constant speed printing traveling section, a step out phenomenon may be caused due to a difference in inertial load, which causes vibration noise.

This problem will be described in more detail.
Now, in a recording apparatus capable of mounting a maximum of two ink heads on a carriage, if the motor drive conditions are set in accordance with one ink head mounted on the carriage, two ink heads will be installed. When mounted and driven, the weight of the carriage increases, causing a problem.

FIGS. 13A and 13B show the transient characteristics of the step motor. The vertical axis represents the rotation angle θ with respect to the elapsed time t (horizontal axis) after the drive signal is applied to the step motor. When the drive signal is applied, the rise time t
After 0, an overshoot occurs, and the vibration stops at the target rotation angle θ1 with a characteristic damping vibration. FIG. 7A shows a case where two ink heads are mounted on the carriage, while FIG. 8B shows a case where one ink head is mounted. Due to the difference in the load characteristics of the carriage, Stop time t
1, t2 is t1> t2. If the ink ejection signal is set to be output to the head at time t2, a step angle error of maximum Δθ1 occurs as shown in FIG. 7A, and the dot pitch in the carriage traveling direction is disturbed.
When the next drive signal is applied during the damping vibration from t0 to t1, the carriage may vibrate and generate noise, and in the worst case, the drive signal and the step rotation cannot be synchronized and a step-out phenomenon occurs. Further, when one ink head is mounted, if the ink ejection signal (or the next drive signal) is set to be given at time t1, the dead time (t1-t2) shown in FIG. Occurs, resulting in a loss of printing speed.

The above phenomenon becomes more remarkable as the number of ink heads mounted on the carriage increases and the difference in weight increases.

An object of the present invention is to solve the above problems and to provide a recording apparatus which reduces recording (printing) noise, improves recording speed, and improves the quality of recorded characters.

[0012]

In order to achieve the above-mentioned object, in the present invention, a recording apparatus is provided with the following (1), (2) and (3).
Configure as follows.

(1) A recording device for performing recording by reciprocating a carriage on which a plurality of recording heads are removably mounted on a recording medium, and a detection means for individually detecting attachment / detachment of the plurality of recording heads. And a control means for controlling a drive signal to the drive source of the carriage according to the output of the detection means.

(2) The recording apparatus according to (1), wherein the recording head is an ink jet recording head integrated with an ink tank.

(3) The recording apparatus according to (1), further comprising a prohibiting means for prohibiting movement of the carriage and / or application of a recording signal when the detecting means detects non-attachment of all recording heads.

[0016]

With the configurations (1), (2), and (3), a drive signal corresponding to the attachment / detachment of the recording head is supplied to the drive source of the carriage. In the configuration of (3), further, when the non-mounting of all the recording heads is detected, the movement of the carriage and / or the application of the recording signal are prohibited.

[0017]

EXAMPLES The present invention will be described in detail below with reference to examples.

(Embodiment 1) FIG. 1 is an external perspective view of a "recording apparatus" which is Embodiment 1. The frame 1, which is formed of a polymer material such as plastic, serves as the base of the printing apparatus and has the functions of a transport mechanism for the recording paper 2, a transport guide path, and a power source. The carriage 3 has two left and right ink heads 4 mounted (only the left side is shown in FIG. 1) and reciprocates in the direction orthogonal to the recording paper 2 conveyance direction. The guide of the reciprocating motion of the carriage 3 is performed by a carriage shaft 5 having both ends fixed to the frame 1 and a guide rail 1a formed integrally with the frame 1.

The carriage 3 has a pair of guide holes 3a which are fitted to the carriage shaft 5 and regulate the movement in the sliding direction.
And a guide rail 1 provided in parallel with the carriage shaft 5.
A guide protrusion 3b for sandwiching a is provided, and only linear movement is allowed. A transport guide path for the recording paper 2 is formed on the upper surface of the frame 1, and a platen surface 6 located at the back of the recording paper 2 at a recording position where ink is ejected and landed from the ink head 4.
a and a platen cover 6 for guiding the entrance of the recording paper 2 into the printing apparatus are attached. Platen surface 6a
Is mounted parallel to the carriage shaft 5 and the guide rail 1a, and when the ink head 4 is mounted on the carriage 3, printing is performed by keeping the distance between the ink head 4 and the platen surface 6a constant over the entire printing area. The ink flight distance is constant. A switch 7 for detecting the position of the carriage 3 is attached to one end of the guide rail 1a of the frame 1, and when the carriage 3 reaches the right limit (pom position), the pair of leaf contacts 7a are short-circuited, and the carriage drive control unit Also, it is used to output a detection signal.

Two ink heads are detachably mounted on the carriage 3, and connection terminals for supplying a print signal to the ink heads are introduced to the ink heads as described later.

The front wall 3e of the carriage 3 is provided with a positioning hole 3c for the ink head 4, and is fitted with a pin 4a (see FIG. 2) protruding from the front surface of the ink head 4. The head 4 is placed at a position facing the front wall of the carriage 3.
Head pressing members 3d for pressing the rear portion toward the front wall to stabilize the contact with the connection terminals and preventing the ink head 4 from coming off are provided corresponding to the respective head mounting positions. Further, on the front wall 3e, a plurality of terminals 8a for supplying a print signal to the ink head 4 are formed on the flexible substrate 8 by a protruding process, and these terminals 8a are connected to a control circuit of the printer. It is electrically connected to the portion 8b by a conductive pattern. The terminals 8a are provided for each ink head in order to supply a print signal to the two left and right ink heads 4. Carriage 3
The flexible boards for the right side ink head and the left side ink head, which are routed in the section, are joined on the left side of the carriage and are integrally connected to the connector section 8b.
A slack portion 8c is provided so as not to prevent the carriage 3 from moving in the entire left and right movement range. Then, the flexible substrate 8 is fixed to the frame 1 by the fastener 9 at the folded back portion. Further, the two fixing members 12 are fixed to the carriage front wall 3e at the tip of the flexible substrate 8 which is fixed to the carriage 3 by the stoppers 10 and on which the terminals 8a are formed.
It is fixed at. On the back surface of the terminal 8a, a damper 18 made of a rubber-like elastic member is sandwiched between the front walls 3e. The damper 18 is set to have a size to be slightly compressed when the ink head 4 is mounted. Therefore, the repulsive force of the damper 18 causes the terminal 8a and the connection terminal 4c on the ink head 4 side.
(Refer to FIG. 2) to stabilize the contact.

Subsequently, a perspective view of the ink head of FIG. 2 and FIG.
The structure of the ink head 4 and the principle of ink ejection will be described with reference to the enlarged cross-sectional view of the nozzle portion of FIG. Inside the ink head 4, there is an ink supply unit 4b containing liquid ink, and on the front surface of the ink head 4, a substrate 4e on which a connection terminal 4c and a thin film resistor 4d are formed is fixed. The same number of ink ejection nozzles 4g are formed at positions corresponding to the thin film resistors 4d, and the periphery thereof is fixed to the substrate 4e by a metal plate 4f sealed to the substrate 4e.
An ink reservoir 4h is formed at the base of the. The ink reservoir 4h communicates with the ink in the ink supply unit 4b and is always filled with the ink. Further, on the front surface of the ink head 4, a pair of positioning pins 4a provided integrally with the case are projected, fitted into the above-described positioning holes 3c of the carriage 3, and used for positioning on the carriage 3.

Since the thin film resistor 4d is located immediately below each nozzle 4g and is connected to the terminal 4c formed on the substrate 4e, when an ink ejection signal is applied to the terminal 4c,
The resistor 4d generates heat and supplies heat to the nearby liquid ink. The heat evaporates the ink in a short time within a few μs, bubbles are generated by the vapor, and the bubbles rapidly grow. The growth of the bubbles transfers the motive force to the ink above, and the ink has a velocity of 10 m / s or more. It passes through the nozzle 4g at a speed and fly as droplets. When the energization of the resistor 4d is completed, the bubbles are reduced, and the ink pool 4h is filled with new ink supplied by the ink supply unit 4b due to the capillary phenomenon.

As shown in FIG. 2, the nozzles 4g are arranged in a vertical line, and the carriage 3 reciprocates with respect to the surface of the recording paper 3. Therefore, by supplying an ejection signal at any time, the dot matrix is formed. Characters, numbers, etc. can be formed on the recording paper 2.

To mount the ink head 4 on the carriage 3, a pin 4a provided on the front surface of the ink head 4 is used.
So that it can be inserted into the positioning hole 3c of the carriage 3 by tilting the front of the head downward and pushing the head pressing member 3d downward while pushing the head pressing member 3d into the recess 3f (see FIG. 1). At this ink head mounting position, the head pressing member 3d urges the ink head 4 forward, so that the terminals 4c come into contact with the corresponding terminals 8a of the flexible substrate 8 and become conductive.

FIG. 4 is a perspective view showing a drive system for the carriage 2 and the recording paper 2. As shown in the figure, the ink head mounting portions 3i-1 and 3i-2 of the carriage 3 each have a detection switch 3h- for individually detecting whether or not the ink head is mounted.
1, 3h-2 are provided and are connected to the circuit pattern of the flexible substrate 8. Reference numeral 13 denotes a step motor as a power source of the drive system. In the present embodiment, a step motor that performs a predetermined step angle rotation by a four-phase excitation signal is used, and reversible operation is performed depending on the phase excitation order. The step motor 13 is fixed to a mounting plate 14, and the mounting plate 14 is mounted on the frame 1.

A timing belt 15 for driving the lower carriage 3 is provided on the shaft 13a of the step motor 13.
A worm gear pulley 16 in which a pulley portion 16a that meshes with the timing belt 15 and a worm gear portion 16b that meshes with a paper feed gear 17 for driving the upper paper feed shaft 19 are integrated is fixed. ing.

The timing belt 15 is stretched in an annular shape on three pulleys 20 rotatably mounted on the mounting plate 14, and is driven in accordance with the rotation of the motor shaft 13a. A part of the timing belt 15 is press-fitted and fixed in the groove of the tip portion 3g of the carriage 3, and transmits power to the carriage 3 guided by the carriage shaft 5 and the rail portion 1a of the frame 1. Further, the paper feed gear 17 is the step motor 1
When the shaft 13a of 3 rotates in the B direction in FIG. 4, it rotates in the D direction. On the other hand, as shown in the sectional view of FIG. 5, a spring clutch 21 is interposed between the paper feed gear 17 and the paper feed shaft 19, and the paper feed gear 17 rotates in the D direction.
The tip of the spring has a paper feed gear 17 so that the inner diameter of the coil increases slightly.
It receives the force from and bends. Therefore, when the rotational force is transmitted by the friction between the inner diameter of the coil portion and the outer circumference of the paper feed shaft 19,
A slip occurs and the rotation of the paper feed gear 17 is not transmitted. In contrast to the rotation of the paper feed gear 17 in the E direction, on the contrary, the inner diameter of the coil portion of the spring clutch 21 becomes smaller, the friction with the paper feed shaft 19 increases, and the paper feed gear 17 rotates in the same direction. Therefore, in FIG. 4, rotation of the motor shaft 13 in the B direction drives the annular timing belt 15 to move the carriage 3 in the F direction, whereas the paper feed shaft 19 does not rotate and paper feed is performed. Absent. Conversely, when the motor shaft 13a rotates in the C direction, the carriage 3 is moved in the direction opposite to F and the paper feed shaft 18 is rotated in the E direction.

A paper feed roller 22 is fixed to the paper feed shaft 19, and at a position corresponding to the paper feed roller 22, a pinch roller 24 is supported by an elastic roller shaft 23 pivotally supported by the mounting plate 14. Paper feed roller 2 with elastic force
It is in contact with 2. The recording paper 2 is the pinch roller 24.
It is supplied to a position sandwiched between the paper feed roller 22 and the paper feed roller 22, and a predetermined amount is fed out by the rotation of the paper feed shaft 19 in the E direction. The print command to the ink head 4 is issued only when the carriage 3 moves in the F direction, and as described above,
At this time, the recording paper 2 is in a stationary state, and desired recording is performed by the ink ejected from the nozzles 7g.

Next, a control system of the recording apparatus will be described by using an example in which the recording apparatus described above is used in an electronic calculator (hereinafter referred to as a calculator).

FIG. 6 is an external perspective view of the calculator. The above-described recording device is housed inside an upper case 50 and a lower case 51 which are casings. A keyboard 50a is located on the upper surface of the front part of the upper case 50, and a plurality of key tops 50b are arranged. This key top is composed of a numeric keypad for inputting numerical values and instruction keys (+, = keys, etc.) for issuing a calculation command, and serves as an input device to a calculation processing device described later. Further, a display device 50c is provided as an output device to visually display numerical value input information and calculation result information. Further, the recording paper 2 wound in a roll on the rear part of the housing is held by the holder 52, and the leading end of the recording paper 2 is supplied into the housing through the recording paper insertion port 50d and is ejected together with the information recorded by the recording device. Exit 50e
More discharged.

FIG. 7 is a block diagram of the control system of the calculator. Reference numeral 25 is an arithmetic processing unit that is configured by using a microcomputer or the like and executes various controls. Reference numeral 50a is a keyboard including a numeric keypad and instruction keys, which is connected to the arithmetic processing unit 25 to input numerical values and arithmetic commands. The arithmetic processing unit 25 outputs a display signal to a display unit 50c for displaying input information and an arithmetic result in response to an input from the keyboard 50a, and outputs a print command code to the print processing unit 26. Based on this print command code, the print processing device 26 outputs a corresponding character code to the character generator 27, discriminates this, and sets the character font in dot units corresponding to the dots of the characters formed by the dot matrix. The signal is returned to the print processing device 26. A print driver 28 amplifies a nozzle drive signal corresponding to the dot matrix provided by the print processing device 26 to an output level required for ink ejection. The ink ejection signal of the print driver 28 is supplied to the printer unit, which is supplied to the ink head 4 via the flexible substrate 8 to eject the ink. On the other hand, the arithmetic processing unit 25 outputs the step motor drive signal to the step motor drive circuit 29 in synchronization with the output of the above-mentioned print command code.

FIG. 8 is a circuit diagram of the step motor 13 and its drive circuit 29. The step motor 13 is a four-phase type having windings L1, L2, L3, L4, and the pulse voltages Φ1 to Φ4 are sequentially applied to each winding, so that the rotating shaft 13a has a step angle of 90 ° from the stationary position. It rotates and makes one rotation by applying four pulse voltages. When the step motor 13 rotates, the worm gear pulley 16 shown in FIG. 4 rotates, and the carriage 3 moves in the line direction (main scanning direction) of the printed characters, and printing is performed in the process.

The step motor drive circuit 29 generates pulse voltages Φ1 to Φ4 at a predetermined timing.
Since the circuits of each phase have the same configuration, only the configuration of one phase will be described. The resistors 291 and 292 are for dividing the input voltage by resistance, and the voltage dividing point is a grounded-emitter NPN.
The base of the type transistor 293 is connected. The collector of the transistor 293 serves as an output terminal, and a series circuit of a diode 294 and a resistor 295 is inserted between this collector and the V _M terminal. Winding L1 for each transistor
One of ~ L4 is connected as a load. One of each winding becomes V _M terminal are commonly connected, the DC power is supplied.

In the structure shown in FIG. 8, when a drive command (“H” level voltage) is applied to the input terminal 296 from the arithmetic processing unit 25, the transistor 293 is turned on and a current from the terminal V _M is applied to the winding L1. Flowing. Note that the voltage induced in the winding L1 at the time of current interruption is the diode 294 and the resistor 29.
It is absorbed by a circuit of five. The resistor 295 also has a function of overcoming the inductance of the winding L1 of the step motor 13 and shortening the rise time of the current. The above is related to the circuit operation of the pulse voltage Φ1, but the same applies to Φ2 to Φ4.

9 (a) and 9 (b) are timing charts according to each operation mode of the drive signal applied to the step motor 13. As shown in FIG. The drive signal controls the energization width for each of the acceleration region where the speed is increased from the stopped state of the carriage 3, the constant speed printing region where the printing operation is performed, and the deceleration region where the carriage 3 is decelerated to stop. The on / off timing of energization is performed in synchronization with the clock pulse CP given from the clock oscillator 31 (see FIG. 7), and the drive signal is generated in the order of Φ1 → Φ2 → Φ3 → Φ4 → Φ1 → .... To do.

FIG. 3A shows a case where two ink heads 4 are mounted on the carriage 3, and Φ1 to Φ in the acceleration region.
In this example, the pulse width of 4 is reduced to 6t, 5t, 4t, and 3t (t is the time of one cycle of CP), and the excitation is performed according to the speed increase of the carriage 3. Further, in the constant-speed printing area, the driving pulse is kept constant at 3t to perform printing by ejecting ink. In the deceleration area following the constant-speed printing area, the carriage 3 is smoothly stopped by increasing the drive pulse width to 3t, 4t, 5t, 6t, contrary to the acceleration area.

When the printing of one line is completed, the carriage 3
Reverse the vehicle to return to the home position. At this time, apply the drive signal to the step motor 13d by Φ
4 → Φ3 → Φ2 → Φ1 → Φ4 → ...
Reverse 3 As a result, the paper feed roller 22 rotates, and the recording paper 2 is conveyed by one line. When the carriage 3 reaches the home position, the switch 7 is operated to cut off the drive signal to the drive circuit 29 and stop the carriage 3.

FIG. 3B shows a case where one ink head is mounted on the carriage 3, and the pulse width of the drive signal is set shorter than that in FIG. 1A in proportion to the reduction of the inertial load of the carriage 3. There is. In the acceleration range, the pulse widths of Φ1 to Φ4 are 5t → 4t → 3t → 2t, and in the constant speed range to 2t.
In the deceleration region, the excitation is 2t → 3t → 4t → 5t. In this way, each energization width is shortened by 1t with respect to FIG. 3A, so that the rotational torque of the step motor 13 is reduced so that the transient characteristics of carriage travel become the same as when two carriages 3 are used. . As a result, the printing noise is reduced, the printing speed can be improved, and the quality of recorded characters is improved.

The timing charts shown in FIGS. 9A and 9B are the information stored in the time table 30 in the block diagram of FIG. The arithmetic processing unit 25 determines which of the two modes is to be used by reading the two ink head detection switches 3h provided in the carriage 3.
It is determined by the detection signals of -1,3h-2. That is,
When both the detection switches 3h-1 and 3h-2 detect the mounting of the ink head 4, the mode shown in FIG. When either one of the detection switches 3h-1 and 3h-2 detects the mounting of the ink head 4, the mode shown in FIG. 7B is selected. Furthermore, the detection switches 3h-1 and 3h
-2, when the non-attachment of the ink head is detected, the arithmetic processing unit 25 may be set not to output the step motor drive signal and / or the print command, and this setting can prevent malfunction.

In this embodiment, the detection switch 3h-
Although the ink head 4 is detected by providing the carriages 1 and 3h-2 in the carriage 3, the following method may be used to detect whether or not the ink head is mounted. That is, as shown in FIG. 10, the detection terminals 4c-1 and 4c-2 connected to each other are provided on the substrate 4e of the ink head 4. A structure may be adopted in which a pair of ink head detection terminals provided on the flexible substrate 8 at positions corresponding to these terminals are short-circuited when the ink head 4 is mounted. In this case, the above-mentioned detection switches 3h-1 and 3h-2 are unnecessary, and the ink head 4 can be detected with a simple configuration.

(Embodiment 2) In Embodiment 1, the presence or absence of the ink head mounting is detected, and one is selected from the drive signal timing information group of the timetable 30 according to the detected state. In addition, the pulse width of the drive signal of the step motor 13 may be converted by appropriately changing the frequency of the reference synchronization signal CP. Example 2 of this example
Will be described with reference to FIG.

In FIG. 11, reference numerals 32a and 32b denote frequency dividers, which sequentially reduce the output frequency of the clock oscillator 31 to 1 /
Divide by 2, 1/4. Further, 33a and 33b are two-input AND gates, and the selection signal output from the arithmetic processing unit 25 is input to one of the input terminals of both. AND gates 33a and 33b are frequency dividers 32a and 32a, respectively.
The divided output of 32b is used as the other input, and when both inputs are both at "H" level, an "H" level signal is output. Reference numeral 34 is an OR gate that takes the logical sum of the output signals of the AND gates 33a and 33b, and the output of the OR gate is applied to the arithmetic processing unit 25 as a clock pulse CP.

Based on the ink head detection information, the arithmetic processing unit 25 outputs a selection signal to either AND gate 33a or 33b. An output signal is generated when the frequency-divided output is applied to the AND gates 33a and 33b to which the selection signal is applied, and this signal is output to the arithmetic processing unit 25 via the OR gate 34. With this configuration, for example, when the number of ink heads mounted is reduced from two to one, the frequency dividers 32a and 32b are operated by the AND gate 3.
A motor having a high frequency of 32b → 32a is selected by 3a and 33b, and the drive signal of FIG. 9B is supplied to the step motor 13.

(Embodiment 3) FIG. 12 is a block diagram of a voltage conversion circuit portion for a step motor drive voltage, which is a main portion of the third embodiment. This embodiment is an example in which so as to vary the amplitude of the drive signal V _M of the step motor 13 on the basis of the ink head mounting information. The voltage conversion circuit 35 includes transistors Tr1 and Tr2 that receive signals output from the arithmetic processing unit 25, a voltage source V _S that supplies power to the collectors of the transistors, and transistors Tr1 and Tr2.
It is composed of a diode D1 connected between two emitters. The output of the voltage conversion circuit 35 is the transistor Tr1.
Is taken out from the connection point between the emitter of the diode and the diode D1. For example, when an "H" level signal is applied to the base of the transistor Tr1, only the transistor Tr1 is rendered conductive, and a voltage of approximately V _S is given to the step motor drive circuit 29 as the drive signal V _M. Next, when an "H" level signal is applied to the base of the transistor Tr2, only the transistor Tr2 becomes conductive, and the forward voltage drop of the diode D1 from the voltage source V _S (≈0.7).
Voltage minus V), i.e., V _M = V _S -0.7V is supplied to the step motor drive circuit 29. Since the step motor 13 generates a rotating torque proportional to the voltage, the motor voltage value V is changed in accordance with the change of the inertial load of the carriage 3.
By controlling _M as appropriate, an optimum driving state can be obtained. In this embodiment, when two ink heads 4 are mounted,
Signal "H" from the arithmetic processing unit 25 to the transistor TR1
Is output and the high voltage is one, the transistor TR
"H" is output to 2 and low voltage is applied to the step motor 13
Added to. That is, the driving voltage value can be switched depending on the detection state of whether or not the ink head is mounted, and the transient characteristics of carriage travel can be made substantially the same regardless of the number of ink heads.

In each of the above embodiments, the maximum number of ink heads is two, but the present invention is not limited to this, and three or more ink heads can be used. You can

Further, in each of the embodiments, the ink head is of a type that ejects ink droplets by causing the ink to change its state using thermal energy, but the invention is not limited to this, and a piezo or the like may be used. Similarly, an electromechanical converter may be used to eject ink droplets.

[0048]

As described above, according to the present embodiment, it is possible to set the driving condition in accordance with the change of the inertial load of the carriage, reduce the recording noise generated during the traveling of the carriage, and improve the recording speed. Also, the quality of recorded characters can be improved.

[Brief description of drawings]

FIG. 1 is an external perspective view of a first embodiment.

FIG. 2 is a perspective view of an ink head

FIG. 3 is an enlarged sectional view of a nozzle portion.

FIG. 4 is a perspective view of a drive system for a carriage and recording paper.

FIG. 5 is a sectional view of a main part of a recording paper drive system.

[Figure 6] External perspective view of a calculator

[Figure 7] Calculator control system block diagram

FIG. 8 is a circuit diagram of a step motor and its drive circuit.

FIG. 9 is a timing chart of drive signals for the step motor.

FIG. 10 is an explanatory diagram of a modification of the first embodiment.

FIG. 11 is a block diagram of a main part of the second embodiment.

FIG. 12 is a block diagram of a main part of the third embodiment.

FIG. 13 is a transient characteristic diagram of a step motor

[Explanation of symbols]

 3 Carriage 3h-1, 3h-2 Ink head detection value switch 4 Ink head 25 Arithmetic processing unit 30 Timetable

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B41J 19/18 Z 9212-2C 29/00 9113-2C B41J 29/00 U

Claims (3)

[Claims] 1. A recording device for performing recording by reciprocally moving a carriage, on which a plurality of recording heads are detachably mounted, on a recording medium, and a detection means for individually detecting attachment / detachment of the plurality of recording heads. And a control unit that controls a drive signal to the drive source of the carriage according to the output of the detection unit. 2. The recording apparatus according to claim 1, wherein the recording head is an ink jet recording head integrated with an ink tank. 3. The recording apparatus according to claim 1, further comprising a prohibiting unit that prohibits movement of the carriage and / or application of a recording signal when the detecting unit detects non-attachment of all recording heads. .