JPH0376061B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a document reading device in a facsimile machine or the like, and particularly to a lighting control device for a light source for document reading.

Discharge lamps (fluorescent lamps) are often used in document reading devices such as facsimile machines, but the on/off control of fluorescent lamps is particularly important because the time required to turn them on (lighting up) depends on the environment (ambient temperature). ) depends on
When the temperature is low, it takes a long time to turn on the light.
Therefore, generally, the filament is preheated to shorten the time until lighting. Direct current, alternating current, or high frequency methods are generally known as methods for preheating the filament, but these preheating methods not only shorten the time until lighting, but also It has various advantages such as long life and stable illuminance. However, in facsimile machines, etc., this preheating is always performed using the standby power supply, so during the standby power supply, the power required to preheat the fluorescent lamp is consumed, and during that time, the filament There were drawbacks such as the fact that current was passed through the lamp, which adversely affected the lifespan of the fluorescent lamp.

The present invention was made in view of the above-mentioned circumstances, and in particular, after the original is set in the original reading device, preheating is started, the original is fed, and then a reading start command is issued from the control device, and the original is read. The preheating time is defined as the preheating time before the document starts to be read, and the fluorescent lamp is turned on when the document starts to be read.This reduces the time required to apply electricity to the filament during preheating, saves power, and reduces the length of the fluorescent lamp. This is intended to extend the lifespan.

Note that it usually only takes a few seconds from preheating to turning on the light, and if the time from preheating to turning on is n seconds, after it is detected that the document is set, the document is fed and moved to the document reading position. It suffices if it takes n seconds or more for the document to start reading.

FIG. 1 is a schematic diagram of the main parts when the document reading device according to the present invention is applied to a facsimile device. In the figure, 1 is a document, 2 is a document transport roller, 3 is a first detector, and 4 is a 2 detector, 5 fluorescent light,
6 is a document holding plate, 7 is a target glass, 8 is a mirror, arrow A indicates the document conveyance direction, and point P indicates the document reading position. A first detector 3 for detecting the presence or absence is provided, and when the first detector detects that a document has been inserted,
An output signal is generated due to this operation, and the roller 2 is driven by a drive system (not shown), such as a pulse motor, and the document 1 is fed to a predetermined position. Furthermore, a second
A detector 4 is disposed downstream of the first detector in the document transport direction, and the feed of the document is stopped midway by the output signal of the second detector.
Wait for reading to start. This reading starts after the handshake with the receiver or at the start of the copy mode (a mode in which one machine has read->write functions), and the document is stopped until these commands are received. As described above, the document passes through the first detector until it reaches the second detector, and the document advances a predetermined amount after passing through the second detector, that is, reaches the document reading position P. Therefore, if you use this time for preheating, you can stop wasting power by constantly preheating, and at the same time,
It is possible to stop the constant energization of the filament due to constant preheating.

Note that the original 1 is detected by the original detector 3 installed near the entrance as described above, and the original 1 is fed by the drive system to reach the reading position, and until the original is actually read. The time required is
The time needed to preheat a fluorescent lamp and turn it on is sufficient.A normal fluorescent lamp can be turned on in two seconds or more after preheating, which is sufficient time to preheat a fluorescent lamp.

FIG. 2 is a diagram showing an example of an electric circuit used in carrying out the present invention, and FIG. 3 is a time chart for explaining its operation. In the figure, 3 is the first detector, 4 is a The second detector, 5 is a fluorescent lamp, 9 is a fluorescent lamp lighting device, and the output signal a of the first detector 3 (the third
(see figure a)) drives the fluorescent lamp lighting device 9 to preheat the fluorescent lamp 5 (see figure 3 c), and the output signal b of the second detector 4 (see figure 3 b) Therefore, the fluorescent lamp lighting device 9 is further driven to light the fluorescent lamp 5 (see Figure 3 d), and from the first detector to the second detector (or reading position). Due to the relationship between the distance of By configuring the document reading device in this way, it is possible to reduce the preheating time to the necessary minimum, achieve power saving, and extend the life of the fluorescent lamp. The lighting device shown in Figure 2 is a device that generates the preheating power and lighting power necessary for the fluorescent lamp using an input power source (DC or AC). The circuit configuration is such that the signal b can supply the power necessary for lighting to the fluorescent lamp, and the output signal of the first detector is used for preheating control, but the present invention is not limited to this. For example, the input power is turned on and off by the output signal of the first detector, and when the input power is turned on, the fluorescent lamp is preheated by the lighting device, and the second
The fluorescent lamp may be turned on by the output signal of the detector. Although FIG. 3 shows control timing using continuous signals, if a latch circuit is provided inside or outside the lighting device, "preheating", "lighting",
The same operation as described above can be performed using trigger pulses for "lighting off" and "preheating off". Furthermore, the third
In FIG. c, the dotted line indicates the case where preheating is cut off after lighting, and lighting can be turned off by setting the output signal of the second detector to a low level.

As is clear from the above description, according to the present invention, the preheating time of the document reading fluorescent lamp of the document reading device is shortened to the minimum necessary time to save the power required for preheating, and the fluorescent lamp It has the advantage of extending its lifespan.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of main parts for explaining an embodiment of a document reading device according to the present invention, FIG. 2 is a diagram showing an example of an electric circuit used for carrying out the present invention, and FIG. , is a time chart for explaining the operation of the electric circuit shown in FIG. 2. 1... Original, 2... Roller, 3... First detector, 4... Second detector, 5... Fluorescent lamp, 9...
Fluorescent lighting device.

Claims (1)

[Scope of Claims] 1. A detection means for detecting the presence or absence of a document, which is provided near the insertion port for the document to be processed, and a light source for reading the document is preheated by an output signal generated due to the operation of the detection means. and means for turning on the light source after preheating the light source and before starting reading the document. 2. The facsimile apparatus according to claim 1, wherein the lighting means includes a second detection means for detecting the presence or absence of a document placed downstream of the detection means in the document conveyance direction. Manuscript reading device.