JPH08214596A - Facsimile - Google Patents

Abstract

PURPOSE: To avoid the step-out of a motor and avoid the mechanical vibration even if a scanning speed of a copy is suddenly accelerated or decelerated by a method wherein a stepping motor is driven at a predetermined stepped speed for the required number of steps corresponding to the stepped speed to accelerate and decelerate successively. CONSTITUTION: The speed of a stepping motor is stepped into 6 steps, i.e., 600, 800, 1200, 1600, 2,000 and 2,400PPS. The stepping motor is accelerated or decelerated while it is driven for the required number of steps of corresponding to the respecteive stepped speeds. Even if the motor speed is changed during reading, the same method can be applied. The required step numbers are stored in a RAM 7b, etc., in accordance with speed characteristics as a control table. In a motor control unit 1, the control table is referred and the stepping motor M is driven for the corresponding number of steps and, after a copy is removed, the motor speed is changed to the motor speed of the next step.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile apparatus which can smoothly and reliably accelerate and decelerate a document scanning speed.

[0002]

2. Description of the Related Art In a facsimile apparatus, when reading and scanning an original image, a motor is driven to convey the original to a reading head, and during reading and scanning, main scanning for one line of the original is completed each time. , It is necessary to feed the document in the sub-scanning direction. The motor speed for this sub-scanning is determined according to the reading mode such as normal, fine, and super fine, and is 2400 PPS and 1200, respectively.
Images are read by PPS and 600 PPS.

Therefore, in the conventional facsimile apparatus, when the reading mode is set to normal, it is necessary to incorporate and drive a motor having a large torque in order to instantaneously increase the motor speed to the maximum speed (2400 PPS).

[0004]

However, in the above-mentioned conventional facsimile machine, the following problems occur especially when the buffer capacity for storing the image data of the read original is reduced for cost reduction or the like. It was
That is, since the capacity of the buffer for storing the image data before reading the document and encoding is small, if the encoding process is delayed due to the transmission process or the like, the scanning for reading the document is temporarily stopped and the motor is stopped. It is necessary to reduce the speed, and then, when the encoding process is completed, perform a synchronization process to accelerate the motor speed in order to restart the reading scan that has been stopped. When the motor speed for reading and scanning is accelerated or decelerated in this way, there is a possibility that a step out of the motor may occur due to the abrupt change in the speed.

If the motor is driven and rotated intermittently, not only the motor itself is vibrated but also mechanical vibrations are generated in each part of the facsimile machine around it, which is a factor of noise, which is not preferable. Further, in order to instantly increase the motor speed, it is necessary to incorporate a motor having a large torque, which causes a problem of high manufacturing cost.

The present invention has been proposed in view of the above points. Even when the scanning speed of a document is rapidly accelerated or decelerated, the motor does not step out and mechanical vibration does not occur. The purpose is to provide by incorporating a small motor.

[0007]

SUMMARY OF THE INVENTION A facsimile apparatus according to claim 1 of the present invention, which is proposed to achieve the above object, drives a step motor at a preset stepping speed for a predetermined number of steps. While accelerating and decelerating, the speed is controlled according to the set reading mode.

Here, the stepping speed is a speed that can be controlled by a step motor, and when the reading mode is normal, for example, 600PPS, 800PPS, 1200PPS, 1 until the maximum speed (2400PPS) is reached.
The speed is divided into each stage of 600 PPS and 2000 PPS. This speed is stepped so as not to cause step-out during acceleration and deceleration.

In the facsimile apparatus according to the second aspect, when the step motor is decelerated at the predetermined stepping speed, the number of steps is set smaller than when the step motor is accelerated. In the facsimile apparatus according to the third aspect, the exciting current of the step motor is gradually reduced as the speed corresponding to the set reading mode becomes smaller.

[0010]

In the facsimile apparatus according to claim 1 of the present invention having the above-mentioned structure, when the motor speed for sub-scanning is accelerated or decelerated in order to adjust the scanning timing for reading the original image. Is performed at the stepping speed. At each stage speed, the step motor is driven for a predetermined number of steps, while the speed is sequentially accelerated and decelerated to a speed according to the set reading mode or stopped. In this way, since the motor speed is controlled by utilizing the inertial force by the stepping, it is possible to smoothly and surely convey the original without step-out.

In the facsimile apparatus according to the second aspect,
When the step motor is decelerated at a predetermined stepping speed, the number of steps is set smaller than when the step motor is accelerated. In other words, during deceleration, it is not necessary to increase the torque as during acceleration, and since the minimum number of steps that does not cause step-out is sufficient, deceleration can be performed quickly. In the facsimile apparatus according to the third aspect, the exciting current of the step motor is reduced stepwise as the speed according to the set reading mode becomes smaller. This is because the slower the motor speed, the more the motor can be controlled even if the exciting current is small. By doing so, even when the motor speed is low, the resonance frequency with the natural frequency of the transport mechanism of the facsimile apparatus does not occur and noise does not occur.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of the configuration of a facsimile device F according to the present invention. The facsimile device F includes a motor control unit 1 for driving and controlling a step motor M applied to convey a document, an image reading unit 2 for reading and scanning an image of a document conveyed by the step motor M, and a desired device. Printout section 3 for printing out the image on the recording paper, numeric keypad and other operation keys, operation section 4 for changing and setting the reading mode, display section 5 composed of a liquid crystal display, etc. It is provided with a line control unit 6 including a modem for transmitting and receiving data, executing switching control of line connection to the communication line L, a storage unit 7 including a ROM 7a and a RAM 7b, and a CPU controlling each of the above units. The control unit 8 is provided.

When the image of the original is read and scanned by the image reading unit 2, the reading mode set by the operation unit 4 (normal,
The document is sub-scanned at a predetermined speed according to fine, super fine, etc.). This speed is 2 in normal
It is 400 PPS, 1200 PPS for Fine, and 600 PPS for Super Fine. The motor control unit 1
From the control unit 8, the number of driving steps, the driving speed, the reading mode,
The step motor M is controlled by receiving the data such as the exciting current value.

According to the present invention, when the scanning speed is changed by changing the reading mode or the scanning speed is changed to synchronize the reading scanning and the encoding process, the stepping motor M is stepped by the motor controller 1. It is characterized by driving at speed. An example of this operation will be described with reference to FIG. In the figure, the vertical axis represents the motor speed (PPS), and the horizontal axis represents the document moving distance (the number of steps).

The motor speed is a preset stepping speed and is controlled to a speed corresponding to the set reading mode.
In the figure, the motor speed is 600, 800, 1200, 16
00, 2000, and 2400 PPS are arranged in six stages, and the drive is accelerated or decelerated while driving for a predetermined number of steps corresponding to each speed (claim 1).
The motor speed is controlled to 2400 PPS when the reading mode is normal, to 1200 PPS when it is fine, and to 600 PPS when it is super fine (hyperfine). Therefore, for example, when reading a document in the normal mode, the symbol a, The motor speed will be changed in the order of b, c ... j, k, l. The same method is also used when changing the motor speed during reading. For example, when decelerating during fine reading, use a,
It is also possible to change the motor speed in the route of b, c, k and return it to the original speed (k to c).

The predetermined number of steps is stored in advance in the RAM 7b or the like as a control table according to the speed characteristic, and the motor control unit 1 refers to this table and drives the step motor M by the corresponding number of steps. Then, after moving the document, the motor speed is changed to the next stage.
FIG. 3 shows an example of the configuration of the control table.

This control table stores two kinds of driving step numbers, that is, the number of acceleration steps and the number of deceleration steps, corresponding to the motor speed at each stage. Therefore, when accelerating the scanning speed of the document. After moving the document for the number of acceleration steps corresponding to the current motor speed, the speed is changed to the next higher speed. On the contrary, when the scanning speed of the document is reduced, the document is moved by the number of deceleration steps corresponding to the current motor speed, and then the speed is changed to the next lower speed.

In this figure, the number of deceleration steps corresponding to the motor speed is smaller than the number of acceleration steps.
That is, when the step motor M is decelerated at a predetermined stepping speed, the number of steps is set smaller than when the step motor M is accelerated (claim 2). This is because it is not necessary to increase the torque when decelerating as in acceleration, and the minimum number of steps that does not cause step-out is sufficient, whereby deceleration of the step motor M can be performed quickly. The contents of this table may be set according to the type of motor, the type of facsimile device F, and the like.

Next, the exciting current when the step motor M is accelerated and decelerated at the stepping speed will be described. The exciting current of the step motor M is gradually reduced as the speed corresponding to the set reading mode becomes smaller (claim 3). This is because as the motor speed is slowed down, the motor can be controlled even if the exciting current is small.

Explaining an example of this operation, when the motor speed is made lower than a predetermined speed (for example, 800 PPS or less), the exciting current supplied to the step motor M is made small (for example, when the motor speed is higher than 800 PPS). The current value is 60% of the current). As a result, when the motor speed is low, the exciting current is large and resonates with the natural frequency of the transport mechanism of the facsimile apparatus F, and noise does not occur. In particular, when the step motor M is intermittently driven and rotated, there is no possibility that each part of the facsimile apparatus F will resonate, and the vibration with a larger amplitude will develop.

The usage of the method of controlling the motor speed of the facsimile apparatus F according to the present invention is not limited. In addition to the facsimile device F, the present invention can be applied to other devices that need to suppress mechanical vibrations caused by step-out and motor driving, such as scanners and printers.

[0022]

As can be understood from the above description, according to the facsimile apparatus of the first aspect of the present invention, the motor speed can be changed stepwise by the small motor having the small torque. The original can be conveyed smoothly and reliably without the motor getting out of step. Further, since a motor having a large torque is not required, the exciting current can be small, noise is not generated, and the manufacturing cost can be reduced.

According to the second aspect of the present invention, the acceleration of the motor speed adapted to the nature of the mechanism of the motor,
Deceleration can be performed with the minimum required number of steps (transportation distance). According to the facsimile apparatus of the third aspect, when the motor speed is low, the resonance with the natural frequency of the transport mechanism of the facsimile apparatus does not occur and noise does not occur.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of the configuration of a facsimile apparatus according to the present invention.

FIG. 2 is a diagram for explaining control of motor speed.

FIG. 3 is a diagram showing an example of a configuration of a control table that stores the number of driving steps of a step motor.

[Explanation of symbols]

 F ... Facsimile machine M ... Step motor 1 ... Motor control unit 2 ... Image reading unit 4 ... Operation unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04N 1/12 A

Claims (3)

[Claims] 1. A facsimile apparatus for reading an image by sub-scanning an original at a predetermined speed according to a reading mode, while driving a step motor by a predetermined number of steps at a preset stepping speed, A facsimile apparatus, which is controlled to a speed according to a set reading mode by sequentially accelerating and decelerating. 2. The facsimile apparatus according to claim 1, wherein when the step motor is decelerated at a predetermined stepping speed, the number of steps is set smaller than when the step motor is accelerated. 3. The facsimile apparatus according to claim 1, wherein the exciting current of the step motor is reduced stepwise as the speed corresponding to the set reading mode decreases.