JPH0368592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for synchronizing a document reading device in an information input device such as a facsimile machine.

Conventional technology A linear pulse motor is a linear pulse motor that is a linear version of a conventional rotary pulse motor.
As shown in FIG. 4, a scale 1 is formed with a large number of parallel grooves so as to have a comb-like cross section, and a slider 3 runs on the scale 1 at a constant interval by a guide roller 2. It is equipped with
A table 4 is provided above the slider 3, and a driven body 5 is mounted on the table 4 as shown in FIG. The scale 1 corresponds to the stator of a conventional rotary pulse motor, and the slider 3 corresponds to the rotor.

As shown in FIG. 6, the slider 3 has electromagnets 7 and 8 each having a U-shaped cross section fixed to different polarity portions of a permanent magnet 6 provided at the bottom of the table 4.
The scale 1 is moved by passing currents in different directions alternately through the coils of the electromagnets 7 and 8. For example, when a positive current is passed through the electromagnet 7, the coil is wound in opposite directions with the a and b poles, so the magnetic force generated at the a pole is added to the magnetic force of the permanent magnet 6, causing the scale to 1. Take the position closest to the upper tooth A,
It becomes stable. On the other hand, the magnetic force generated at the b pole acts to cancel the magnetic force of the permanent magnet 6. Next, when a positive current is applied to the electromagnet 8, the d pole and the tooth D attract each other, and the slider 3 moves to the right by 1/4 of a pitch. This time, when a negative current is passed through the electromagnet 7, the b pole and the tooth B
are attracted to each other, and the slider 3 further moves 1/4 pitch to the right. Then, when a negative current is passed through the electromagnet 8, the c pole and the tooth C attract each other, and the slider 3 further moves to the right. Move forward 1/4 pitch. and,
By applying a positive current to the electromagnet 7 again and subsequently applying a current in the same manner, the slider 3 can be sequentially moved to the right.

Such linear pulse motors have been used in printer head drive mechanisms, X-Y tables, X-Y plotters, etc. in the past.

The pitch of the scale used in such devices is generally manufactured to have a movement of 1/60 inch/pulse (two-phase excitation) according to the specifications of the device. Currently, a device with even higher resolution of 1/120 inch/pulse is being developed.

Incidentally, such a device is generally used with a high degree of stopping accuracy, but when a linear pulse motor is used to drive an optical unit of a document reading device, running performance is required rather than stopping accuracy.

On the other hand, such a device is operated by synchronizing the timing of the operation of the driven body and the timing of supplying pulses to the pulse motor.

Problems to be Solved by the Invention However, the sub-scanning line density of the reading device is 200,
In the case of 400 lines/inch, there arises a problem that the operating position of the motor at these sub-scanning line densities cannot be synchronized with the timing of supplying pulses to the pulse motor.

This problem arises because the conventional scale pitch was originally developed in the inch series and used with a travel distance of 1/60 inch/pulse. The place,
Not technically resolved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a method for synchronizing a document reading device that synchronizes the timing of a reading scan and the timing of supplying pulses to a pulse motor.

Means for Solving the Problems In order to achieve the above object, the present invention provides an original reading device equipped with an optical unit provided on a slider of a linear pulse motor to optically read a stationary original. The ratio between the number of pulses and the number of sub-scanning lines is calculated from the value obtained by multiplying the number of sub-scanning lines by the sub-scanning line density, and based on this calculated value, the reading scanning timing and the timing of supplying pulses to the pulse motor are synchronized. Features.

Function By multiplying the movement amount of the pulse motor per pulse by the sub-scanning line density, dividing this, and using the ratio as the number of pulses to be supplied to the number of lines, the read scan timing and the pulses to the pulse motor can be adjusted. synchronize with the supply timing.

Embodiment FIGS. 1 and 2 are a schematic front view and a schematic side view, respectively, of a document reading device according to an embodiment of the present invention. In the figures, numerals 1 to 4 correspond to the numerals given to the same members in FIGS. 5 to 7. The optical unit 10 includes a fluorescent lamp 11, a reflecting mirror 12, a condensing lens 13, a reading element 14, and a drive circuit 15, and a guide roller attached to a fixed adapter 16 provided at the bottom of the optical unit 10. It is fixed to the slider 3 via 2. Note that the optical unit 10 may include a contact type image sensor. Also,
Another guide roller 1 attached to the adapter 16
7 guides the movement of the slider relative to the scale 1.

Next, the operation will be explained.

The original 19 placed on the original table glass 18 is
It is fixed with a document holder 20 and illuminated with a fluorescent lamp 11. After the reflected light has its optical path changed by the reflecting mirror 12, it is focused onto the reading element 14 via the condensing lens 13. This reading element 14 is electronically main-scanned by a drive circuit 15 to perform processing such as photoelectric conversion.

On the other hand, the sub-scanning is performed by the optical unit 10 as the slide 3 to which the optical unit 10 is fixed moves in the direction along the scale 1 at a predetermined speed.

Here, a method of synchronizing the reading scan timing and the timing of supplying pulses to the pulse motor will be explained.

Note that the amount of movement of the pulse motor is 1/x ₀ inch/pulse in two-phase excitation.

When the sub-scanning line density is x ₁ line/inch,
Multiply 1/x ₀ and x ₁ and reduce it.

x ₁ / x ₀ = x ₁ ′ / x ₀ ′ (x ₀ = ax ₀ ′, x ₁ = ax ₁ ′, a is a common divisor of x ₀ and x ₁ ) This gives the x ₁ ′ / x ₀ ′ line /pulse would mean X ₀ ' pulses per x ₁ ' line.

Therefore, the cycle of the reading scan timing and the timing of supplying pulses to the pulse motor should be determined by the ratio of the reading scan x ₁ ' line to the number of pulses supplied to the pulse motor x ₀ ', as shown in Figure 3. I can do it.

To give a specific example, if the travel distance of the pulse motor is 1/60 inch/pulse in two-phase excitation, and the sub-scanning line density is 200 lines/inch, then 1/60 x 200 = 10/3 line/pulse. becomes. Therefore, it is sufficient to supply three pulses to the pulse motor for ten lines of read scanning.

Furthermore, if the sub-scanning line density is 400 lines/inch, then 1/60×400=20/3 lines/pulse. Therefore, three pulses are supplied to the pulse motor for 20 lines of read scanning.

Effects of the Invention According to the present invention, since the ratio between the number of pulses of the pulse motor used for sub-scanning and the sub-scanning line is calculated, the reading scan timing and the timing of supplying pulses to the pulse motor are determined based on this value. This has the effect of being able to synchronize.

[Brief explanation of drawings]

1 is a schematic front view of a document reading device according to an embodiment of the present invention, FIG. 2 is a schematic side view of the document reading device shown in FIG. 1, and FIG. 3 is a schematic side view of the document reading device shown in FIG. Timing chart diagram, Figure 4 is a perspective view of the linear pulse motor, Figure 5 is a front view of the linear pulse motor shown in Figure 4, and Figure 6 is the operating state of the scale and slider in the linear pulse motor shown in Figure 4. It is a partial sectional view for explaining. 1...Fixed scale, 3...Slider, 10...
...optical unit.

Claims (1)

[Claims] 1. In a document reading device equipped with a linear pulse motor including a slider whose fixed scale is moved by a guide roller at a constant interval, and an optical unit provided on the slider to optically read a stationary document, one pulse By multiplying the amount of movement of the pulse motor per unit by the sub-scanning line density, dividing this, and using the ratio as the number of pulses to be supplied to the number of lines, the timing of the read scan and the timing of supplying pulses to the pulse motor can be adjusted. A method for synchronizing a document reading device, characterized in that synchronization is achieved.