JPH01253473A - Scanning device - Google Patents

Abstract

PURPOSE:To detect a malfunction with respect to the movement of a carriage by providing comparing means for comparing an operation state detected by operation state detecting means with a reference signal generated from reference signal generating means to output a signal responding to an incoincidence when the comparison result is incoincidence. CONSTITUTION:A slit plate 5 attached to the rotary shaft of a motor 3, and a photosensor 6 for detecting light penetrating the slit upon rotation of the plate 5 are provided. When a drive signal is applied to the motor 3, the motor 3 is rotated, and its rotary driving force is transmitted to a carriage 7 through a pulley 1 and a timing belt 2 to move the carriage 7. Simultaneously, the plate 5 attached to the motor 3 is rotated, and the slit formed on the plate is detected by the photosensor 6. Thus, a driving pulse to the motor 3 is compared with the actual rotary amount of the motor 3, and a malfunction of the rotation of the motor 3 is detected when the comparison result is incoincidence.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scanning device for performing recording while moving a carriage carrying a recording head or a reading head using a stepping motor.

(Prior Art) As a device of this type, a carriage drive mechanism in a conventional printer is configured as shown in FIG. 8, for example. In the figure, 1 is a pulley, 2 is a timing belt, 3 is a stepping motor, 4 is a guide shaft, and 7
is a carriage 7, and 78 is a recording head mounted on the carriage 7.

In this configuration, when a drive signal is applied to the motor 3, the motor rotates, and the rotational driving force of the motor 3 is applied to the pulley 1.
It is transmitted to the carriage 7 via the timing heald 2,
This allows the carriage 7 to move left and right on the guide shaft 4.

[Problem to be solved by the invention]

However, the above conventional example has the following problems. In other words, a stepping motor is generally known as a motor that responds to drive signals without making any mistakes. When a load is applied to the motor, the motor may not rotate in synchronization with the drive signal and may step out, or the rotational speed may change, making it impossible to move the carriage accurately and recording at the correct position. On the other hand, conventional printers have a problem in that even if an abnormality occurs, it is impossible to deal with it because there is no means for detecting such abnormal rotation of the motor.

The present invention has been made in view of the above-mentioned conventional problems, and its object is to provide a scanning device equipped with means for detecting abnormalities in carriage movement.

(Means for Solving the Problems) To achieve this, the present invention provides a carriage that is driven by a stepping motor, carries a recording head or a reading head, and performs a recording operation, and an operation state detector that detects the operation state of the carriage. the means, the reference signal generating means for generating a reference signal indicating a predetermined operating state of the carriage, the operating state detected by the operating state detecting means and the reference signal generated by the reference signal generating means; The present invention is characterized in that it includes a comparing means for outputting a signal corresponding to the above.

(Function) According to the above configuration, the predetermined moving state (for example, speed) of the carriage is compared with the actual moving state, and when the comparison results in a discrepancy, the output from the comparing means is used to Abnormal movement of the carriage can be detected.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a perspective view of a carriage moving mechanism showing an embodiment of the present invention, and in this figure, elements similar to those shown in FIG. 8 are designated by the same reference numerals, and their explanation will be omitted. The configuration of this embodiment is different from the configuration shown in FIG. This is because the sensor 6 is provided.

In the configuration shown in FIG. 1, when a drive signal is given to the motor 3, the motor 3 rotates, and this rotational driving force is applied to the pulley 1,
is transmitted to the carriage 7 via the timing belt 2,
Carriage 7 moves.

At the same time, the slit plate 5 attached to the motor 3 also rotates, and the photosensor 6 detects the slit provided in the slit plate.

As a result, the drive pulse to the motor 3 and the actual motor 3
It is detected that the rotation of the sharpening motor 3 whose comparison does not match is abnormal. This abnormality detection will be explained below with reference to FIGS. 2 and 3.

Figure 2 is a timing chart of signals related to carriage movement, in which a and b are motor drive signals (2
(phase excitation) and d are motor phase switching timing pulses generated from the motor drive rJJJ signals a and b. f, g,
h is an output signal from an encoder composed of a slit plate 5 and a photosensor 6, and due to the relationship between the slit interval and the motor drive signal, every five timing pulses d are generated, the encoder Output signal f is 1
It is configured to output 1. Here, g and h are outputs generated in a certain abnormal rotation state.

FIG. 3 is a block diagram of a circuit for detecting abnormal rotation of the motor. In the figure, 8 is a timing pulse generation circuit that generates a motor phase switching timing pulse based on motor drive signals a and b, and 9 is a slit plate 5. and a photosensor 6; 10 and 11 are counters that count pulses from the timing pulse generation circuit 8 and the encoder 9, respectively; 12 is a counter 1;
13 is a comparison circuit that compares the output of the latch circuit 12 with the contents of the reference pulse number circuit 14, and 14 is a reference pulse number circuit that generates the reference pulse number. . 15 is a motor control circuit, 16 is an error processing circuit, and 18 is an element for notifying an error, such as an LED, a buzzer, or an LCD.

When the counter 10 counts five motor phase switching timing pulses d, it resets the counters lO and 11, and at the same time transfers the value of the counter 11 at that time to the latch circuit 12.
The value of the latch circuit 12 is output to the comparison circuit 13. When the motor rotates normally, the encoder 9 is output every five motor phase switching timing pulses d.
Since one pulse is output from , the reference pulse number 14 is set to "°1".

When the drive pulses a and b are input and the motor 3 starts rotating, the motor phase switching timing pulse d is counted as shown in FIG.
When this happens, it resets itself and the counter 11. At the same time, the output of the counter 11 is held in the latch 12, but if the motor is operating normally, while counting five motor phase switching timing pulses d,
Since there is one output from the encoder 9 (see f in FIG. 2), the output of the latch circuit 12 is "1pa".Here,
The comparison circuit 13 compares this value with the value "1" stored in the reference pulse number 14. While the motor is rotating normally, the comparison results in a match, so the output from the comparison circuit 13 has no effect on the motor control circuit 15 and the error processing circuit 16.

On the other hand, if the carriage 7 is prevented from moving due to a recording paper jam, etc., or if its movement is accelerated by some action, the output from the encoder 9 will be
Alternatively, as shown in h, one or more motor phase switching timing pulses d are output while five motor phase switching timing pulses d are output, or they are not output at all. As a result, the value held in the latch circuit 12 is other than °゛1'',
A mismatch occurs in the comparison circuit 13, and the output from the comparison circuit 13 due to this mismatch is sent to the motor control circuit 15.
, are supplied to the error processing circuit 16. This causes loss of synchronization,
Abnormalities such as recording defects 1 paper jams are detected, and it is possible to stop the motor or display the occurrence of an error.

In addition, here, motor phase switching timing pulse 5
Although the number of output pulses from the encoder is one for each n number of output pulses, it is also possible to output one pulse of °C for every n number of output pulses.

In realizing the above embodiment, exactly the same effect can be achieved by using a signal obtained with the configuration shown in FIG. 4 as the output of the encoder for comparison with the motor drive No. 13. In FIG. 4, reference numeral 19 indicates a photo sensor 20 every time n motor phase switching timing pulses d are generated.
This is a band-shaped slit plate that detects one pulse. The signal obtained from this photosensor 20 is shown in FIG.
, g.

h, it can be handled exactly the same as the output of the encoder 9 in FIG.

FIG. 5 is a perspective view of a carriage moving mechanism showing a second embodiment of the present invention.
This is a DC tachogenerator attached to the rotating shaft of a pulley 22 disposed at the other end.

When the motor 3 starts rotating, the speed gradually increases until it reaches a constant speed state. Along with this, the voltage generated by the tachogenerator 21 also increases and becomes a constant voltage when the speed becomes constant. This situation is not shown in Figure 6. Closing i is a constant speed valid signal that becomes valid only when the motor 3 is at constant speed, and j indicates the output waveform of the tachogenerator during normal operation. Here, if the movement of the carriage 7 is hindered for some reason, the output waveform of the tachogenerator during constant speed drive is disturbed as shown by h in FIG. 6.

Here, as shown in the block diagram of FIG. 7, when the comparator 13A is gated by the constant speed effective signal i manually inputted from the terminal 23, the output of the DC tachogenerator 21 and the tachogenerator at constant speed Reference voltage 22 which is the voltage of 21
are compared in the comparator 13Δ. At this time, the 6th
As shown at h in the figure, if the movement of the carriage 7 becomes unstable and the output of the tacho generator is disturbed, the comparator 13A
The output of motor control circuit 15. indicates that an error has occurred. Although the description has been given regarding a carriage with an error, a similar effect can be obtained with a scanning mechanism of a carriage equipped with a reading hent.

(Effects of the Invention) As is clear from the above description, according to the present invention, the predetermined sliding state of the carriage is compared with the actual moving state, and when the comparison or mismatch occurs, the output from the comparing means is used to Abnormal movement of the carriage can be detected.

As a result, if there is any abnormality in the movement of the carriage due to a jam in the recording paper, etc., the problem will occur in the recorded image by stopping the motor or displaying an error message upon knowing that an error has occurred. The effect was that it was possible to prevent this from occurring.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a carriage drive mechanism showing an embodiment of the present invention, Fig. 2 is a timing chart of the carriage drive shown in Fig. 1, and Fig. 3 is abnormality detection in the carriage drive shown in Fig. 1. A block diagram of the circuit, FIG. 4 is a perspective view showing a modification of the embodiment shown in FIG. 1, FIG. 5 is a perspective view of a carriage drive mechanism showing the second embodiment, and FIG. 7 is a block diagram of an abnormality detection circuit involved in the carriage drive shown in FIG. 5, and FIG. 8 is a perspective view showing a conventional carriage drive mechanism. 3...Dryer, 5.19...Slit plate, 6.20...Front sensor, 7...Carriage, 9...Encoder, 10, 11...Counter, 12. ...Latch circuit, 13...Comparison circuit, 13Δ...Comparator, 14...Reference pulse number circuit, 21...DC tacho generator, 22...Reference voltage.

Claims (1)

[Scope of Claims] 1) a carriage driven by a stepping motor, carrying a recording head or a reading head and performing a recording operation; an operation state detection means for detecting an operation state of the carriage; a reference signal generating means for generating a reference signal indicative of a predetermined operating state; and comparing the operating state detected by the operating state detecting means and the reference signal generated by the reference signal generating means, and responding accordingly if they do not match. 1. A scanning device comprising: comparing means for outputting a signal obtained by comparing the signals.