JPH01219774A - Controller for original scanning part - Google Patents

Abstract

PURPOSE:To perform an original scanning control fitting a machine type without changing parts and adjusting a pressure, etc., by setting the control pattern of a driving motor according to a load put to the driving motor of an original scanning part. CONSTITUTION:In an image forming device to form an image by scanning an original, a slave CPU 11 to carry out a program from a ROM 13 receives signals which are start command signals such as a mirror start command, a mirror initial command, etc., from a master CPU 10, and the signals from a home position sensor HPS and from the rotary encoder RE of an original scanning driving motor 9, and calculates a time required according to the load put to the motor 9. Then, according to the result of a calculation, the control pattern of the motor 9 is set, so that the motor 9 is controlled. Consequently, the original scanning control fitting the machine type can be performed without changing the parts and adjusting the pressure, etc., like a control by a fixed control pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION (Al Industrial Field of Application) The present invention relates to a document scanning section control device of an image forming apparatus that scans a document using a document scanning section including a light source, a mirror, and the like.

(b) Conventional technology In an image forming apparatus for copying original images, a document table is provided on which the document to be copied is placed, and a document scanning section including a light source, a mirror, etc. is provided below the document table. The document is copied by moving the document scanning section along the document table and forming an image of reflected light from the document on the photoreceptor.

The original scanning section has the light source, mirror, etc. built into a unit that moves back and forth along rails, wires, etc. If the moving speed of the document scanning unit is too fast, too slow, or fluctuates, the document may not be scanned smoothly and blur may occur in image formation. Therefore, generally, a drive motor for moving the document scanning section is controlled by a servo system including a PID control system, etc., and the moving state of the document scanning section is controlled. In a control device that controls the moving speed of the document scanning unit using such a servo system, a control pattern for the servo control system is stored in advance, and the moving speed is controlled in accordance with the control pattern. Generally, the control pattern is fixed and cannot be changed for each machine such as a copying machine.

(The problem that the C1 invention aims to solve is that the fitting condition of the light source, mirror, etc. to the rail, the frictional force due to the tension pressure of the wire, etc. differ from machine to machine,
The load applied when the document scanning unit moves varies from machine to machine, and as mentioned above, if the control pattern is fixed, document scanning speed cannot be controlled accurately, resulting in image blur, image skipping, blurring, etc. There was a problem. One way to solve this problem is to check the fitting condition of the light source, mirror, etc. to the rail and the tension pressure of the wire on the production line, and then replace parts and adjust the pressure, but this is a waste of time. There were drawbacks such as requiring additional parts and poor yields of parts.

In view of the above drawbacks, the present invention enables parts replacement by setting a control pattern for the driving motor according to the load applied to the original scanning unit driving motor.

It is an object of the present invention to provide an original scanning unit control device that can perform original scanning control suitable for the machine stand without performing pressure adjustment or the like.

(d) Means for Solving the Problems The document scanning unit control device of the present invention is an image forming apparatus that scans a document to form an image using a document scanning unit including a light source, a mirror, etc. The control is provided with a required time detection section for measuring the required time corresponding to the load applied to the original scanning unit driving motor, and means for setting a control pattern for the original scanning unit driving motor based on the required time. (13) Effect: According to the original scanning unit control device of the present invention, the required time corresponding to the load applied to the original scanning unit driving motor, for example,
■Time required for the original scanning unit to reach a specified speed, ■Time required for the original scanning unit to move a predetermined distance detected by the position sensor, ■Output of the rotary encoder (RE) by the motor that drives the original scanning unit. The time required to rotate a predetermined number of times detected by counting pulses is measured, and a control pattern for the document scanning unit driving motor is set based on the required time. The larger the load applied to the document scanning unit, the longer the required time, and the smaller the load, the shorter the required time. By setting a control pattern based on the required time, the motor for driving the document scanning section, that is, the document scanning section can be accurately controlled.

if) Embodiment FIG. 1 is a perspective view of a main part of a document scanning section of a copying machine which is an embodiment of the present invention.

The document scanning unit includes a mirror base MBI that integrates a light source 1 and a mirror (not shown) disposed below the light source 1;
It has a mirror base MB2 integrated with a mirror 2.3 that receives the reflected light from the mirror of the mirror base MBI and guides the reflected light to a light receiving system (not shown). These mirror bases MBI and MB2 are supported by two rails 4.5 so as to be slidable in the horizontal direction. The side portion 1a of the mirror base MBI is fixed to the wire 6, and the mirror base MB2 receives the two-speed driving force of the wire 6 via a deceleration double pulley (not shown). The wire 6 is wound around a pulley 7.8 and a rotating shaft of a DCC morph, which is a motor for driving the document scanning unit, and rotates as the motor 9 rotates forward or backward.

As a result, the mirror base MBI moves in the feed direction F or the return direction R at the same speed as the rotation speed of the wire 6, and the mirror base MB2 moves at a speed equal to the rotation speed of the wire 6.
It moves in the feed direction F or return direction R at the same speed.

The wire fixing side portion 1a of the mirror base MBI has a vertical piece 1b. Further, a home position sensor HPS is provided near the stop position of the mirror base MBI to detect the vertical piece 1b. The home position sensor HPS is designed to turn on when the mirror base MBI is at the stop position and turn off when the mirror base MBI starts and reaches a specified speed required for document scanning. It is set in.

FIG. 2 is a professional diagram of the control section of this copying machine.

This copying machine is controlled by a mask slave system. The main control of this device is performed by the master CPU (MCPU) according to the program stored in the ROM12.
It is done by 10. The MCPUIO receives input from each input key 1 and various sensors, sends commands to a slave CPU (SCPU) that controls each operating section, and receives status from the 5 CPUs.

5 cpui 1 is C for controlling the original scanning unit including motor 9
The PU controls the document scanning unit according to a program stored in the ROM 13 in advance. 5CPLIII is MC
In addition to receiving commands such as a mirror start command and mirror initial command from PUIO, it also receives signals from the rotary encoder RE of the motor 9, home position sensor HPS, etc., and determines the optimal control pattern for the motor 9 according to these receptions. settings to control the rotation of the motor 9.

FIG. 3(B) is a diagram illustrating the time required to set the control pattern of the motor 9, which is detected by the required time detection section (timer).

The motor 9 is turned on at to, a constant current is applied, and the document scanning section starts. When the motor 9 is turned on, the rotary encoder RE starts counting and the timer starts measuring time. At tl, the document scanning section reaches the specified speed, and the time T1 required until then varies depending on the magnitude of the load applied to the motor 9. That is, since a constant current is always applied to the motor 9, the time required for the document scanning section to reach a predetermined speed corresponds to the load applied to the motor. Note that the fact that the document scanning section has reached the specified speed is detected by the pulse interval of the rotary encoder RE.

Further, the Bauhm position sensor HP S turns off at t2, and the time required up to that point T2 becomes the time required to move a predetermined distance (distance from the stop position to the home position sensor i (ps off position)). Furthermore, at t3, the counter that counts the output pulses of the rotary encoder RE counts up, and the time required up to that point T3 becomes the time required for the motor 9 to rotate a predetermined number of times. This is used as a reference for determining the drive timing of the PS roller to convey the image to the transfer section at a predetermined timing.

These required times T, , T2. All T3 correspond to the magnitude of the load applied to the motor 9. Therefore, by setting a control pattern for the motor 9 based on any of these required times T, , Tt, and T3, the document scanning section (motor 9) can be controlled in accordance with the load.

FIG. 4 is a diagram showing an example of control pattern settings, with the horizontal axis representing magnification and the vertical axis representing gain. The magnitude of the gain represents the responsiveness of the servo control system. Therefore, as the gain increases, the target value (specified speed) is reached faster in proportion to the gain.
Control of current to the motor is performed. From this, the control pattern is set so that the smaller the load, the thicker the gain.Also, as the magnification becomes smaller, the speed of the document scanning section becomes faster, so it is necessary to increase responsiveness, so the gain is set to The control pattern is set so that the fourth
The figure shows this relationship. Note that this control pattern was determined to some extent through actual measurements. In the figure, the shorter the required time, the more the motor 9 is applied (the more it is added to the document scanning section)
Since the load can be considered small, the control pattern is set so that the gain for the same magnification is large, and the required time T
Since it can be considered that the longer +n is, the larger the load is, the control pattern is set so that the gain for the same magnification is smaller. The control pattern may be stored in advance in the ROM as in this embodiment, or may be stored as a pattern function.

FIG. 5 is a flowchart showing a processing program for setting control patterns.

When a specific switch is operated, such as at the end of a production line,
The 5 CPUI sets a preliminary scanning mode for driving the original scanning unit and setting a control pattern. here,
The document scanning unit moves from the stop position to the home position sensor HP
An example is shown in which the time required to move a predetermined distance until S is turned off is measured and a control pattern is set. Note that in the preliminary scanning mode, a control pattern (reference control pattern) in which the load applied to the motor 9 is standard is set, and document scanning is performed.

When the preliminary scanning mode is set, the reference control pattern is set, the document scanning section moves in the feed direction, a timer starts, and speed control is performed (n 1
-=n2-n3). If the home position sensor HPS turns off (n4), this indicates that the document scanning section has moved a predetermined distance, so the required time T2 is memorized (n5), and the document scanning section is returned (n6).

At step n7, an appropriate control pattern is set based on the required time T2 and the relationship between the required time and the control pattern shown in FIG. For example, if the required time is longer than the required time under standard load, then the control pattern is set so that the gain at the same magnification is smaller than the gain under standard load, and from then on, the control pattern The gain is set in accordance with this, and the motor 9 of the document scanning section is controlled.

When the establishment of the control pattern is completed, status (No. 8) indicating completion of preliminary scanning is sent to the MCPU at n8.

FIG. 6 is a flowchart showing a control pattern setting processing program for the document scanning unit motor 9 representing another embodiment. In this program, a control pattern is set based on the required time corresponding to the number of rotations of the motor 9.

When the preliminary scanning signal is received, a reference control pattern is set, the counter C is cleared, the document scanning section is fed, and the timer is activated (nll-n12). The document scanning section is accelerated at n13, and this acceleration control is continued until it is determined at n16 that the current speed has reached the specified speed. The number of rotations of the motor 9 during this period is detected by the rotary encoder RE and counted by the counter C (n14, n15). When the current speed reaches the specified speed, constant speed control is performed at n17. Even during constant speed control, the number of rotations of the motor 9 is counted by the counter C (
n18. n19), when the count number C reaches the preset number CN (n20), the time required up to that point T
3 is stored (n21), and the document scanning section is returned (n22). At n23, a control pattern is set based on the required time T3 1. Once the control pattern is set, the 5 CPU 1 sends a pre-scan end signal to the M CPU (n24) and ends the pre-scan.

Preliminary scanning is performed as described above, and a control pattern is set. If the control pattern is set by performing a preliminary scan when the copier is initially turned on, the control pattern can be set in response to changes in load over time of use. Therefore, the motor 9 can be controlled well.

(g) Effects of the Invention According to the original scanning unit motor arrangement of the present invention, the control pattern of the original scanning unit driving motor can be set according to the load applied to the original scanning unit driving motor, so that There is no need to replace parts according to the control pattern, improving yield during manufacturing.Also, the control pattern can be easily set by simply scanning the document scanning unit, reducing adjustment time. There is also an advantage in that the control pattern can be set according to the wear of the document scanning section during use of the device, etc.Furthermore, it is possible to set the control pattern according to the load applied to the document scanning section drive motor. This has the advantage that the document scanning section can be well controlled and image formation can be performed accurately.

[Brief explanation of the drawing]

Fig. 1 is an external view of a document scanning unit applied to a copying machine that is an embodiment of the present invention, Fig. 2 is a block diagram of a control unit of the copying machine, and Fig. 3 is a diagram showing the time required to measure. It is. FIG. 4 is a diagram showing an example of a control pattern, and FIG. 5 is a diagram showing a processing program during preliminary scanning of the copying machine. Furthermore, FIG. 6 is a flowchart showing a processing program during preliminary scanning in another embodiment. 9-motor, 10-MCPU. 11-3 CPU (for document scanning unit control), MBI-mirror base, 1-IPS-home position sensor.

Claims (1)

[Claims] (1) In an image forming apparatus that scans a document and forms an image using a document scanning section including a light source, a mirror, etc., the time required to correspond to the load applied to the document scanning section driving motor when the document scanning section is moved. What is claimed is: 1. A document scanning section control device, comprising: a required time detection section for measuring the required time; and means for setting a control pattern for a document scanning section driving motor based on the required time.