JPH0481778B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an optical part braking device, and more particularly, to an optical part braking device for accurately stopping an optical part at a home position.

<Prior Art> In a copying machine that exposes an original by moving an optical part, it is necessary to ensure that the optical part reaches a predetermined moving speed at the time when exposure of the original starts. After completing the exposure of the original, the optical unit must be accurately returned to the home position and stopped.

In order to stop the optical part accurately at the home position, there has conventionally been a method in which braking is performed for a predetermined period of time from the time when the optical part returns to a predetermined position before the home position. The second type detects the backward movement speed of the optical part at a predetermined position and applies braking for a predetermined period of time corresponding to the backward movement speed. It was provided.

<Problems to be solved by the invention> Based on the above configuration, the optical braking device has the following problems:
The stopping position varies depending on the load on the optical part.
There is a problem in that when the load is heavy, the copying machine stops in front of the home position, whereas when the load is light, it passes past the home position and collides with the main body of the copying machine.

Furthermore, with the optical braking device configured as described above, it is possible to accurately stop the copying machine at the home position when the load is heavy, but when the load is light, the copying machine can be stopped at the home position. There is a problem of collision with the main body.

With the optical braking device with the above configuration, the braking time is given according to the return speed, so it is possible to significantly improve the stopping position accuracy compared to the optical braking device with the above configuration. It is possible, but it does not take into account the start position of the double movement, so
To be more precise, there is a problem in that it cannot be stopped exactly at the home position. To explain this problem in more detail, the relationship between the return speed of the optical section and the braking time required to stop it at the home position is as shown in Figure 4. If the backward movement start position determined by changes, the required braking time will differ even if the backward movement speed is the same. Therefore, even if the braking time is controlled solely based on the backward motion speed, a problem arises in that it is impossible to accurately stop a document of a certain size at the home position. I will do it. In addition, the one-dot broken line in Fig. 4 shows the constant condition characteristics determined by the load on the optical section, etc. In the same figure, the indications such as A3 and A4 indicate that the double movement start position is for A3 and A4 size documents, respectively. This indicates the corresponding position.

<Object of the Invention> The present invention has been made in view of the above problems, and provides an optical part braking device that can accurately stop the optical part at the home position regardless of the scan distance of the optical part. It is intended to.

<Means for Solving the Problems> In order to achieve the above object, the optical part braking device of the present invention is configured to stop the optical part reciprocating relative to the document at the home position during the return movement. In the optical part braking device, a return movement start position detection means detects the return movement start position of the optical part, a return movement speed detection means detects the return movement speed of the optical part at the time when the optical part moves back to a predetermined position, and the above-mentioned It is characterized by comprising a time calculation means for calculating the required braking time based on the backward movement start position and the backward movement speed, and a control means for driving the braking means for braking the optical system for the required braking time. be.

<Function> With the optical part braking device having the above configuration, when the optical part is moved backward after the forward movement with respect to the document is completed, the backward movement start position is detected by the backward movement start position detection means, and then, When the backward movement position detecting means detects that the backward movement has reached a predetermined position, the backward movement speed of the optical part is detected by the backward movement speed detection means, and the calculation means is performed based on the backward movement start position and the backward movement speed. The required braking time is calculated, and the control means drives the braking means for the calculated required braking time to brake the optical section.

<Examples> Hereinafter, examples will be described in detail with reference to the accompanying drawings showing examples.

FIG. 5 is a schematic diagram showing the main parts of a copying machine, which has an optical system 2 below a contact glass 1, and below it a copy processing section 3 and a copy paper conveyance section 4. There is.

The optical system 2 includes a light source 21, reflecting mirrors 22, 2
3, 24, a lens 25, and a reflecting mirror 26, the light source 21 and the reflecting mirror 22
While moving at a predetermined speed, the reflecting mirrors 23,
24 in the same direction at half the above-mentioned predetermined speed, the original D set on the contact glass 1 can be exposed. Hereinafter, the light source 21 and the reflecting mirrors 22, 2
3 and 24 are collectively referred to as an optical section 2'.

Note that 27 is a light shielding plate that moves integrally with the light source 21 and the reflecting mirror 22, and 28 and 29 are photo interrupters driven by the light shielding plate 27. A photo interrupter 28 is attached corresponding to the home position.

The copy processing section 3 has a charging charger 32, a blanking lamp 33, a developing device 34, a transfer charger 35, a separation charger 36, and a cleaner 37 arranged in this order around a photosensitive drum 31 that rotates in one direction. .

The copy paper conveying section 4 includes the photosensitive drum 31
The copy paper is conveyed one sheet at a time in synchronization with the rotation of the register rollers 41, and only the registration rollers 41 are shown in the figure.

FIG. 1 is a block diagram showing the electrical configuration of the optical braking device.
A signal obtained by shaping the signal from the pulse encoder 51 and the signal from the pulse encoder 51 by the waveform shaping circuit 52 is supplied to the CPU 54 via the input port 53.
A control signal from 54 is supplied to a driver circuit 56 via an output port 55, and an output signal from the driver circuit 56 is supplied to a DC motor 57.

The pulse encoder 51 outputs a pulse signal in synchronization with the rotational speed of the DC motor 57. Also, 58 is ROM, 59 is RAM
It is.

The operation of the optical braking device having the above configuration will be explained with reference to the flowchart shown in FIG.

In the step, the various parts necessary for carrying out the copying operation are initialized, and in the step, the process waits until the print key or the like is operated and it is requested to move the optical part 2' forward. Thereafter, in step, the optical section 2' is moved forward at a predetermined speed required for exposure by driving the DC motor 57 in forward rotation at a constant speed (see a in FIG. 3B), and in step After waiting until the optical section 2' reaches a position where forward movement of the optical section 2' is stopped, the position of the optical section 2' is detected in a step. Detection of this position is
This is done by calculating the number of pulse signals output from the pulse encoder 51.

Thereafter, in step, the optical section 2' is accelerated in the backward direction by driving the DC motor 57 at full speed in the reverse direction (see b in Fig. 3B). The backward movement speed of the optical section 2' is detected. Detection of this backward movement speed proceeds during one clock signal of the clock signal output from the pulse encoder 51 via the waveform shaping circuit 52.
This is done by calculating the count number of the counter of the CPU 54.

Thereafter, in a step, the required braking time is calculated based on the position of the optical part 2' detected in the above step and the backward movement speed calculated in the above step. This required braking time is calculated as the time corresponding to the point on the corresponding straight line in the characteristic diagram of FIG.

Therefore, in step, the optical part 2' is braked by driving the DC motor 57 in full forward rotation (see c in Figure 3B), and in step, the required braking time calculated in the above step elapses. Wait until 1, stop the drive of the DC motor 57 in step, determine whether or not continuous copy mode is selected in step, and if it is not selected, continue with the determination processing below step, and if it is selected,
The determination processing below the step is performed as it is.

To summarize the above, even if the backward movement speed is the same at the time when the optical part 2' is detected by the photo interrupter 29, if the backward movement start position changes, the required braking time will be changed. 2' can be accurately stopped at the home position.

Note that the present invention is not limited to the above-mentioned embodiments, and for example, it is possible to determine that the photo interrupter 28 is operating for confirmation when the drive is stopped in a step. In addition, various design changes can be made without changing the gist of the invention.

<Effects of the Invention> As described above, the present invention sets the required braking time by taking into account not only the backward movement speed but also the backward movement start position, so that the optical section can be reliably positioned at the home position in any case. It has the unique effect of being able to stop at any point.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the optical braking device, Fig. 2 is a flowchart, Fig. 3 is a diagram explaining the operation of the optical part, and Fig. 4 is a diagram showing the relationship between the backward movement speed and the required braking time. FIG. 5 is a schematic diagram showing the main parts of the copying machine. 2'...Optical section, 29...Photo interrupter,
51...Pulse encoder, 54...CPU, 5
6...driver circuit, 57...DC motor.

Claims (1)

[Claims] 1. In an optical part braking device for stopping an optical part reciprocating relative to a document at a home position during the return movement, a return movement start position detection means for detecting the return movement start position of the optical part, and a return movement start position detection means for detecting a return movement start position of the optical part; a backward movement speed detection means for detecting the backward movement speed of the optical part at the time when the optical part moves backward to the point where the optical part moves backward; a time calculation means for calculating the required braking time based on the above-mentioned backward movement start position and the backward movement speed; 1. An optical part braking device, comprising: a control means for driving a braking means for braking an optical part.