JPH01237570A - Scanner positioning method - Google Patents

Abstract

PURPOSE:To position a scanner with high accuracy by providing a stopper on a stop position of the scanner, and detaining the scanner to its stopper. CONSTITUTION:The upper limit of a supply current to a scanner driving motor is controlled to a prescribed value or below in the vicinity of a scanner stop position, a scanner MB1 is detained to stoppers 5a, 5b provided on the scanner stop position and positioned, thereafter, the supply current is stopped. In such a way, when the scanner MB1 is detained to the stoppers 5a, 5b and stopped, the supply current to the driving motor of the scanner MB1 is controlled to a prescribed value or below in the vicinity of the stoppers 5a, 5b. Therefore, the stop position of the scanner MB1 can be positioned exactly, and also, it is prevented that a large burden is applied to a driving circuit of the motor, when the scanner MB1 is detained to the stoppers 5a, 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field This invention is a device for moving a scanner by motor drive, in which the scanner is positioned and stopped. There are two types of things. One type scans documents by using a drive motor to feed a scanner containing a light source along a fixed document table (a copying machine with a fixed document table), and the other uses a fixed light source. On the other hand, the copying machine scans the original by moving the original using an original moving device (original moving type copying machine). Conventional copying machines are equipped with either a scanner or a document moving device as described above, but none have both.Therefore, it is necessary to position and fix the movably supported scanner and move the document. In such a copying machine, a scanner must be movably supported and fixed at a lower portion of a document moving device.

Control using a scanner drive motor can be considered to fix the scanner, but with motor control alone, the positioning accuracy when the scanner is fixed is poor at about ±5 fins, and when scanning the original, it becomes out of focus and the quality of the copied image is poor. The problem has been how to improve scanner positioning accuracy.

An object of the present invention is to provide a stopper at the scanner stop position and to lock the scanner to the stopper.
An object of the present invention is to provide a scanner positioning method capable of positioning a scanner with high precision.

(C) Means for Solving the Problems This invention controls the upper limit of the current supplied to the scanner drive motor to a predetermined value or less near the scanner stop position, and locks the scanner to a stopper provided at the scanner stop position. The feature is that the supply current is stopped after the positioning is performed.

If this optical section is applied to a copying machine that includes both a fixed document table and a document moving device, a document placed on the document table is scanned and copied by moving a scanner.

Further, when a document moving device is used, if a stopper is provided at the lower part of the document moving device, the scanner is latched to this stopper and stopped. At this time, the current supplied to the scanner's drive motor is controlled to a predetermined value or less near the stopper, reducing the burden on the motor and driver even if the scanner is latched to the stopper and the drive motor is locked. . Immediately after the scanner is locked to the stopper, the current supply is stopped and the locked state is released.

At this time, since the scanner is locked to the stopper, positioning has already been performed.

(1111 Embodiment FIG. 1 is a block diagram of a copying machine to which the scanner positioning method of the present invention is applied.This copying machine includes a document table on which a document is placed, and a cylindrical document feeder (hereinafter referred to as It's called RDH.

). A manuscript of A3 size or smaller, a book, etc. can be placed on the document table, and the document is scanned by moving a scanner (mirror base) along the document table.

Further, the RDH can automatically feed a sheet-like original of A4 size or smaller, and a scanner (mirror base) is fixed to the lower part of the RDH to scan the original.

A drum-shaped photoreceptor 1 is disposed approximately at the center of the upper part of the main body of the copying machine, and a charging section, a developing section, a transfer section, a static eliminating section, etc. are provided around the photoconductor 1 to constitute an image forming process section. On the right side of the photoconductor 1 is a paper feed section 5 that includes a paper feed tray and a cassette mounting section and supplies paper to the image forming process section, and on the left side is a transport section 6 that transports the paper after toner transfer. A fixing section 7 includes a roller and performs fixing of a toner image, and a paper discharge section 8 for discharging a fixing sheet is further provided on the left side thereof. Further, at the bottom of the copying machine main body, there is provided an intermediate conveying section 9 for temporarily docking sheets when performing double-sided copying, composite copying, etc.

On the top of the copying machine body, there is a document table 2 made of transparent glass, etc.
and RDH3 are arranged. The RDH 3 includes cylindrical drums 3a and 3b, a document feed/discharge tray 3C1, and a document transport section 3d. The cylindrical drum 3a is used for front side copying, and the cylindrical drum 3b is used for backside copying, and the original wound around the cylindrical drum 3a on the outside of the front side is switched back and wound around the cylindrical drum 3b on the outside of the back side. The document wrapped around the cylindrical drum 3a is scanned by a mirror base (scanner) described later at an exposure point P1, and the document wrapped around the cylindrical drum 3b is scanned by a mirror base (scanner) at an exposure point P2. be done. - When making multiple copies from a sheet of original, the original is scanned continuously by continuously rotating the cylindrical drum 3a or 3b, and when scanning the original placed on the original platen 2. Compared to this, mirror base return time is not required, so high-speed processing is possible. After copying is completed, the document is ejected to the document feed/discharge tray 3C by the document transport section 3d.

An optical section 4 is provided at the top of the copying machine main body. The optical section 4 includes a light source 4a, mirrors 4b to 4e, and a lens 4.
It has f. The light source 4a exposes the original placed on the original platen 2 or the original wrapped around the cylindrical drums 3a and 3b, and the mirrors 4b to 4e and the lens 4f direct the reflected light from the original to the exposure point P of the photoreceptor 1. lead

FIG. 2 is a perspective view of essential parts of the optical section 4.

Light source 4a and mirror 4b are fixed to mirror base MB1, and mirror 4C and mirror 4d (not shown) are fixed to mirror base MB2. These mirror bases MBI and MB2 are scanners according to the present invention. The mirror bases MBI and MB2 are slidably supported by two rails 41 and 41. The side portion 42 of the mirror base MBI is fixed to a wire 43, and the mirror base MB2 receives the two-speed driving force of the wire 43 via a double pulley 44 for deceleration. The wire 43 has both ends fixed to a fixed part (not shown), is wound around the pulleys 45, 46, 47, and the rotating shaft of the motor 48, and rotates as the motor 48 rotates forward and backward. This allows the mirror base MBI to
0 rotation speed and the same speed, and mirror base MB2 has 2 speeds of wire 430 rotation speed, respectively in the feed direction F.
Or move in the return direction R. The mirror base M
A vertical piece 42a is provided on the side portion 42 of the BI, and a home position sensor 48 is provided at the home position HP of the mirror base to detect that the mirror base MBI is at the home position HP.

Stoppers 5a and 5b for locking the mirror base MBI are provided below the exposure points P1 and P2.

Stoppers 5a and 5b are solenoids 51a and 51, respectively.
b, compression springs 52a, 52b, locking member 53a,
53b. When the solenoids 51a and 51b are in the off state, the locking members 53a and 53b move in the direction of arrow A due to the force of the springs 52a and 52b, enter the movement range of the mirror base MBI, and lock the locking portion 42b of the mirror base MBI. Lock it. Also, solenoids 51a and 51b
When in the on state, the locking members 53a and 53b move in the direction of arrow B against the force of the springs 52a and 52b, and are removed from the movement range of the mirror base MBI.

FIG. 3 is a block diagram of the control section of the copying machine. The copier is controlled by a master-slave system.

The master CPU (MCPU) 61 controls each slave CPU (SCPU) according to the program stored in advance in the ROM 62 in response to input from the input key 1 various sensors, etc.
Send a command to. 63 is 5 CPU for controlling the optical part
In response to the mirror start command, mirror initial command, etc. sent from the MCPU 61, the ROM 6
4 and input signals from the home position sensor HPS, motor rotary encoder RE, etc., control signals are output to the driver 65 and ON/OFF signals are output to the solenoids 51a and 51b.

In the driver 65, for example, turning on the transistor Tr,
By controlling the off duty ratio, the motor 4
Controls the supply current to 8. Based on the output from the rotary encoder RE etc., the 5 CPU 63 to the driver 65
A duty ratio control signal is output, and the driver 65 controls the duty ratio according to the signal. The duty ratio changes the on time. or by changing the off time. rotary encoder RE
If the current speed input from the motor 48 is slower than the speed target value, the duty ratio is set large and the current supplied to the motor 48 becomes large, and if the difference between the current speed and the speed target value becomes smaller, the duty ratio becomes smaller. This setting reduces the current supplied to the motor 48. Note that the voltage across the detection resistor R connected in series with the motor 48 is detected, and the current applied to the motor 48 reaches the maximum current limit value (I+, 1 in FIG. 6).
The output pulse to the transistor Tr is controlled so as not to exceed xr>.

Under normal conditions, the upper limit of the duty ratio is set to about 90%, and when the mirror base starts moving, current is supplied to the motor 48 at a duty ratio of about 90%. If the device is used for a long time at a duty ratio of about 90%, there is a risk of damage to the transistor Tr, etc. However, in normal conditions, the time required for acceleration is short, so damage can be avoided. However, if the mirror base MBI is latched to the stoppers 5a and 5b at a speed with a large duty ratio, even if the current is stopped immediately after that, a large current will rush in when the motor is locked when stopped, and the transistor Tr
may damage the motor or burn out the motor coil. Therefore, in order to prevent this, if the upper limit of the duty ratio is set to, for example, several percent to 30% before the mirror base MHI is locked to the stopper 5a or 5b, the mirror base MBI can be fixed to the stopper 5a or 5b. Even if the motor is engaged with the motor and becomes locked, it is possible to prevent a large current from rushing in at that moment, thereby preventing damage to the transistor Tr and burnout of the motor coil.

FIG. 4 is a diagram showing the moving state of the mirror base MBI, and FIG. 5 is a flowchart showing the processing procedure of the 5 CPU 63. In addition, FIG. 5(A) shows the mirror base MB.
FIG.
This shows the processing procedure when moving the image to the exposure point P1. In addition, Mirror Base MB2 is Mirror Base MBI.
Move % distance at a speed of .

First, the case of scanning a document placed on the document table 2 will be explained (FIG. 5(A)).

When the 5CPU 63 receives a command to scan the document on the document table 2 from the MCPU 61, the 5CPU 63 sets the upper limit of the duty ratio of the motor 48 to 90% in nl, and thereafter controls the duty ratio at the upper limit of 90%. Next, the motor 48 is rotated in the normal direction,
The mirror base MBI is moved in the feed direction at a speed of (n2-n3). At this time, the original on the original platen 2 is scanned, and the reflected light is guided to the photoreceptor. The rotation of the motor 48 is detected by a rotary encoder RE, and this detected value corresponds to the distance from the home position HP of the mirror base MBI. If the trailing edge of the document is A, the trailing edge A can be detected by the rotary encoder RE. When the mirror base MBI reaches the rear end A, the motor 48, which was rotating in the forward direction, is braked.
Subsequently, driving is started in the reverse direction (n 4-”n
5-n 6). As a result, the mirror base MBI moves in the return direction R, is braked twice, and the motor 48 is stopped at the home position sensor HPS position to complete the document scanning process.

In addition, when using RD H3, mirror base MBI
is moved to the exposure point P1 or P2 and fixed in position. The flowchart in FIG. 5(B) shows the processing procedure for positioning at the exposure point P1, and the solid line from the home position HP in the return direction in FIG. 4 shows the state of the mirror base MHI at that time. There is. In addition, exposure point P2
The same processing procedure is used when positioning is performed.

First, when a command to move to the exposure point P1 is sent from the MCPU 61, the 5CPU 63 sets the upper limit of the duty ratio to 90% with nil, and the solenoid 51a with n12.
Determine whether the is on or off. If the solenoid 51a is not off, that is, the locking member 53a is
If it is not in the BI movement range, the solenoid 51a is turned off and the locking member 53a is moved (n13). When the mirror base is at the home position HP, the following process is performed, but when it is at a position other than the home position HP, for example, when it is at the exposure point P2, other processes are performed and the mirror base MBI is moved to the exposure point P1. (n14). However, the process when stopping the mirror base MBI at the exposure point P1 is similar to the process below.

At n15, the motor 48 is driven in reverse, and the mirror base M
BI is moved in the return direction R. The target speed in this case is V4, and the duty ratio is set large until reaching V4 speed, for example, close to 90%, and the following is ■4
The vehicle runs stably at high speed (n16). FIG. 6 is a diagram showing the voltage and current applied to the motor 48 at this time,
VMI represents the motor voltage, and ■□ represents the motor current. Note that RE represents a pulse generated by the rotary encoder RE. (2) During stable running at 4 speed, the duty ratio ('r+/'r) is controlled at about 60 to 70%. When mirror base MBI reaches point B, motor 4
8, the target speed is set to the speed ■, and the upper limit of the duty ratio ('r, /T') is set to 30% (n17-"n18), mirror base MHI is traveling at a speed reduced to ■ (n
19), and is locked by the stopper 5a. At this time, since the upper limit of the duty ratio of the motor 48 drive circuit is set and controlled at 30%, a large load is not placed on the transistor Tr, etc., and damage to the transistor Tr, etc. can be prevented. . mirror base MBI
When the motor 48 is engaged with the stopper 5a and the motor 48 is longitudinally moved, the detection by the rotary encoder RE disappears, the current supply is stopped, and the motor 48 is turned off (n20→n
21). The mirror base MBI is securely positioned because it is locked to the stopper 5a.

In addition, ■□ and ■□ in Fig. 6 are motor voltages of other examples,
The maximum current limit value is switched from ■1 to ■2 when the motor current is decelerated to the speed ■, and the maximum current limit value is switched from ■1 to ■2, thereby increasing the current supplied to the motor 48 and applying the scanner positioning method of the present invention. Since the motor drive current is stopped after the scanner is engaged with the stopper, the stop position of the scanner can be accurately determined. Therefore, when used for positioning a scanner (mirror base) in a copying machine, it is possible to prevent defocus and the like from occurring and form a good image. In addition, since the upper limit of the current supplied to the motor is set below a predetermined value near the scanner stop position, it is possible to prevent a large load from being placed on the motor drive circuit when the scanner is latched to the stopper. This has the advantage of preventing equipment damage and burnout.

2 is a perspective view of the main part of the optical section of the copying machine, and FIG. 3 is a block diagram of the control section of the copying machine. Furthermore, FIG. 4 is a diagram showing the moving state of the mirror base, and FIG. 5 is a diagram showing the processing procedure of 5 CPUs that drive the mirror base.
3A shows the processing procedure when positioning and fixing the mirror base, and FIG. 1B shows the order of processing elements when scanning the document on the document table. Furthermore, FIG. 6 is a diagram showing the voltage and current applied to the mirror base drive motor.

MBI-mirror base (scanner), 5a, 5b-stopper, 51a, 51b - solenoid, 52a, 52b-spring; 53a, 53b-locking members.

Claims (1)

[Claims] (1) Control the upper limit of the current supplied to the scanner drive motor to below a predetermined value near the scanner stop position, position the scanner by locking it to a stopper provided at the scanner stop position, and then stop the supply current. A scanner positioning method characterized by: