JPS6344647A - Copying machine - Google Patents

Abstract

PURPOSE:To copy originals at a prescribed density by a low exposure energy by beginning to charge a main capacitor for a flash lamp after a platen plate attains a 1st set temperature and making the flash lamp emit light when the platen plate reaches a 2nd set temperature and when the main capacitor is charged to a prescribed potential. CONSTITUTION:When the platen plate is heated, a temperature control part monitors a signal from a temperature detection thermister provided close to the platen plate or provided by bringing into contact with said plate. When the platen plate attains the 1st prescribed temperature, 40 deg.C, for instance, an operation control parts starts charging the main capacitor. When the platen plate attains the 2nd prescribed temperature, 45 deg.C, for instance, a signal is again transmitted to the operation control part, and conduction to a heater stops. According to the signal that the thermister detects, the temperature control part continues or cut the conduction to the heater hence onward, whereby the temperature of the platen plate is kept within a given range, 45-50 deg.C, for instance. When charging the main capacitor is completed, the operation control part outputs a display to show that the flash lamp can light up.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copying apparatus that copies original images using a heat-sensitive copying sheet.

As a simple and inexpensive copying device or plate-making machine that does not require an aperture system including a virtual imaging lens or a photoreceptor,
2. Description of the Related Art Copying apparatuses are known that use a copying sheet consisting of an ink sheet having a heat-melting ink layer and a transfer sheet, or a heat-sensitive copying sheet such as a heat-sensitive coloring sheet.

In this copying machine, for example, as shown in FIG. 9, heat feJr! A document 5 with the image side facing downward is placed on a copy sheet 4 in which an ink sheet 2 having an A-based ink layer 2a and a transfer sheet 3 are superimposed, and pressure is applied with a pressure plate 6, so that the copy sheet 4 is placed under a platen glass 1. By causing the flash lamp 7 to emit light and exposing the document to light that has passed through the copy sheet 4, the image area of the document 6 drawn in black generates heat, and this heat causes the portion of the ink sheet 2 corresponding to the document image to become heated. The ink layer is selectively melted and transferred to the transfer sheet 3, and the original image is copied. In addition.

If necessary, the ink image on the transfer sheet 3 is thermally transferred to another transfer paper.

Now, in the copying apparatus having the above structure, the ink layer of the ink sheet is melted by the heat generated in the original image area due to exposure, or the heat-sensitive coloring sheet is caused to develop color.

In order to make a copy with the required density, exposure with considerably high energy is required, and there are problems in that the exposure si becomes expensive and power consumption increases.

Purpose of the present invention In view of the above-mentioned actual situation of a copying apparatus that makes copies using a heat-sensitive copying sheet, the present invention is capable of copying with a required density through low-energy exposure, and has reasonable Tr & source load fluctuations. The purpose of this invention is to provide a copying device that is easy to use and easy to use.

In order to achieve the above-mentioned object, the present invention provides a copying apparatus having the above-described structure, which includes a heater for heating the platen plate, and when the tti source switch of the copying apparatus is turned on, the platen plate heater is turned on. After the platen plate reaches the first set temperature, charging of the flash lamp main capacitor starts, and the platen plate reaches the second set temperature and the main capacitor reaches the predetermined potential. The present invention is characterized by comprising a control device that controls the flash lamp so that it can emit light when the flash lamp is fully charged.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment of a copying apparatus to which the present invention is applied.

A platen glass 1 is provided on the top plate of the copying device 10,
As mentioned above, the pressure plate 6 that presses the ink sheets, transfer sheets, and originals stacked on the pressure plate 6 swings within an angular range near the center of the pair of arms 11 pivotally attached to the rear end of the top plate of the copying machine main body. It is mounted so that it can move freely. A pressurizing handle 12 is provided by connecting the front ends of the pair of arms 11. A xenon lamp 7 is installed at the bottom of the platen glass 1 as a dew point source.
is provided. As shown in detail in FIG. 2, the pressure plate 6 is made up of an elastic member 14 such as a foam material attached to the lower surface of the elastic support cover 13, and furthermore, an elastic member 14 such as a foam material is attached to the lower surface of the pressure plate 6 for heating the platen glass 1 according to the present invention. Planar heating element 15
is installed. The surface of the planar heating element 15 facing the platen glass 1 is made reflective white. Figure 3 (a
), (b), and (c) are diagrams each schematically showing the configuration of the planar heating element 15. (a) What is shown in the figure is a tungsten thin film on a white resin film 16 such as a silicone resin film with mold releasability, or a white film 16 such as synthetic paper.
Or resistance heating element layer 1 formed by carbon coating
7 is laminated. (b) The one shown in the figure is (a) the one with the structure shown in the figure but with a protective layer 18 provided on the surface of the white film 16, and (c) the one shown in the figure is also protected on the outer surface of the planar heating element layer. A layer 18 is provided. These layers may be laminated with an adhesive or heat-sealed to form a laminate. Since the white film layer 16 or the protective layer 18 covering it is attached to face the platen glass 1, during exposure, it reflects the irradiated light outside the area of the document and absorbs the irradiated light into the heating element 17. Furthermore, the reflected light beam can be returned to the reflecting plate near the light g7 again.

As shown in FIG. 1, next to the platen plate 1 on the top plate of the copying machine 10, there is a switch S that is pressed when the pressure plate 6 is closed.
W1 is provided. Further, an operating section 19 is provided on the front side of the top plate of the copying device.

FIG. 4 shows a blinking circuit of the resistor 17 of the planar heating element 15. The resistor of the planar heating element may be one that completely covers the entire lower surface of the pressure plate 6, or may be one that has a pattern such as a strip shape formed thereon. In this example, the total resistor is 2
．． , divided into two parts of 22, and two parts Z-engineered!
As shown in FIG. 4, the power supply 22 is turned off when the temperature of the platen glass 1 reaches a predetermined temperature by a signal from the switch SWI and the thermistor (not shown) that detects the temperature of the platen glass 1. If the voltage drops below this level, the voltage application control switch SW2 and resistor 2□, z2 will be turned on.
They are connected via a change-over switch SW3 that can selectively switch energization between series and parallel.

When starting up from a low temperature state, changeover switch SW3 is set to both paper antibodies 21.2. When the pressure plate 6 is closed, the SWI is turned on, and SW2 is also connected because it is low temperature, and the resistors 2L and 22 are energized with a voltage of ff1WX20, and the temperature of the resistor rises to a certain temperature. do. Therefore, the changeover switch SW3 is switched to series energization. By doing this, half the voltage is applied to each of 21.2 degrees,
Narrow the temperature control range and use the voltage application control switch SW2
The temperature of the platen glass is maintained at a constant ff
Can be maintained at one time. Since SWl is disconnected in state 1 when the pressure plate 6 is open, it is possible to prevent unnecessary heating of the air by energizing the resistor with the pressure plate open.

By raising the temperature of the platen glass higher than room temperature, the heat-sensitive copying sheet, such as a heat-melting ink sheet, placed on it during copying can be heated within a range where reactions such as ink f8m or color development do not occur. Therefore, less energy is required to react the heat-sensitive copy sheet than if the platen glass were at room temperature.

Figure 5 shows an example of the experimental results showing the relationship between the temperature of the platen plate and the luminous energy per unit area required to cause the heat-sensitive copying sheet to react. Emission energy is approximately 1.8J/a
J, and when the temperature of the platen plate is 50'C, the required light emission energy is about 1.2 J/cd, and it can be seen that the light energy is only about 2/3.

The higher the temperature of the platen plate, the more energy for exposure can be reduced. However, if the temperature of the platen plate is set too high, unnecessary parts of the background will be transferred during exposure, and background stains will easily occur.

Further, by setting the heating temperature of the platen plate to a temperature higher than the maximum temperature of the environment where the copying machine is placed, stable image forming conditions can be obtained that ignore changes in the environment temperature. For these reasons, the temperature of the platen plate is 40 to 55.
It is desirable that the temperature be controlled within a range of approximately ±3°C.

As described above, according to the present invention, the sight of the exposure light source can be reduced, but when a flash lamp such as a xenon lamp is used as the exposure source, it is necessary to charge the main capacitor in order to emit light. is necessary.

When controlling the temperature of an image forming part such as a platen plate using a heater such as a planar heating element as in the copying apparatus of the present invention, the time required for heating by the heater, the time required to charge the main capacitor, and the heating time for these It is necessary to control the battery in consideration of short-term load fluctuations associated with charging and charging.

An example of a desirable control operation will be explained based on the flowchart shown in FIG. 6 and the block diagram shown in FIG. 7.

First, what about the equipment by the operator? ! ! The source is put in.

As a result, electricity is started to be applied to the heater for heating the platen plate, and the platen plate is heated. A signal from a temperature detection thermistor provided close to or in contact with the platen plate is monitored by a temperature control unit, and the temperature is set to a first predetermined temperature (for example, 40°C).
When this happens, a signal is sent to the operation control unit. The operation control section starts charging the main capacitor based on this signal. When the platen plate reaches a second predetermined temperature (for example, 45° C.), a signal is sent to the operation control unit again, and the power supply to the heater is stopped. After this, the U degree control section maintains the platen plate temperature within a constant range (for example, 45 to 50''C) by turning off and on the power supply to the heater based on the detection signal of the thermistor.

The operation control section outputs a display indicating that the flash lamp can be lit when the second signal from the temperature control section and charging of the main capacitor are completed.

After the display appears, when the operator turns on the light emitting switch, a trigger voltage is output from the trigger circuit in the operation control section to the lamp, and the flash lamp emits a flash of light. In the operation control section, after the main capacitor is discharged.

The battery will be charged again and will be ready for the next lighting.

By performing such control, it is ensured that the temperature of the platen plate always remains within a constant condition during light emission.

The temperature control level is the first. The reason for having the second and second stages is to charge the main capacitor at the same time as the heating of the heater, thereby eliminating wasted time. Therefore, if the charging time of the main capacitor is very short, the first. Charging may be started after the initial heating of the platen plate is completed by setting the second level to the same level (that is, setting only the second predetermined level).

However, T! ! It is not preferable to start both heater heating and main capacitor charging at the same time when gSW is turned on.

The reason for this is (a) the rush current when the power switch is turned on becomes large. (b) After charging is completed early, the self-discharge of the main capacitor must be further charged, which is wasteful. (c) Another control system is required to charge the main capacitor at a different timing. etc.

Further, in this case, since the heater is energized and the main capacitor is charged at different times, the load can be reduced from the power source's perspective. Not only at startup, but also afterwards, when the main capacitor is being charged, a signal is sent from the operation control section to the temperature control section, and by stopping power supply to the heater during that time, the load for heating the heater and the load for charging the main capacitor are reduced. Loads do not overlap and only a small amount of current is required.

(1), (2), and (3) in Figure 8(a) are timing diagrams of heater heating and main capacitor charging and their superimposition when heater heating and main capacitor charging overlap in time. The load curve is (1) and (2) in Figure 8(b).
) and (3) are similar curves when the timings of heater heating and main capacitor charging are shifted so that they do not overlap. This figure shows how the load is reduced when the timing of heater heating and main capacitor charging is shifted.

Note that the energization time required to heat the platen glass at startup is longer than the energization time required to heat the platen and charge the main capacitor after startup, so platen heating takes the lead until the first temperature is reached. After that, by controlling the capacitor charging, convenient control can be performed.

Effects As described above, according to the present invention, when copying using a heat-sensitive copying sheet, copies can be made at a predetermined density with low exposure energy, power supply load fluctuations are reasonable, and control is convenient for use. be able to.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a copying apparatus to which the present invention is applied, FIG. 2 is a sectional view of its pressure plate, and FIGS. 3(a) and (b).
) and (c) are cross-sectional views showing various configurations of the planar heating element, FIG. 4 is a circuit diagram showing a blinking control circuit when the resistor of the planar heating element is divided into two, and FIG. 5 is a circuit diagram showing the platen. A curve diagram showing an example of the relationship between the temperature of the plate and the luminous energy per unit area required for reacting the heat-sensitive copying sheet, FIG. 6 is a flowchart showing an example of the control operation of the apparatus of the present invention, and FIG. Its block diagram, FIG. 8(a),
(b) is a timing chart of the power supply load when the heating of the platen plate heater and the charging of the flash lamp main capacitor are made to overlap and when they are not made to overlap. FIG. 2 is a schematic diagram illustrating a copying method using a heat-sensitive copying sheet. 1... Platen glass (transparent platen plate) 2... Ink sheet 3... Transfer paper 4... Heat sensitive copying sheet 5... Original 6... Pressing plate 10... Copying device 15... Planar heating element 16... White sheet SWI... Switch that is pressed down by a pressure plate to energize the heating element. ) September 24, 1986

Claims (4)

[Claims] (1) A heat-sensitive copy sheet and an original are stacked in this order on a transparent platen plate, pressurized with a pressure plate, and the original is exposed to light transmitted through the heat-sensitive copy sheet using a flash lamp installed below the platen. A copying apparatus that copies an image of an original onto the heat-sensitive copying sheet based on the difference in heat generation between the image area and the background area of the original has a heater that heats the platen plate, and when the power switch of the copying apparatus is turned on. After the platen plate heater is turned on and the platen plate reaches the first set temperature, charging of the flash lamp main capacitor is started, the platen plate reaches the second set temperature, and . A copying apparatus comprising a control device that controls the flash lamp so that it can emit light when the main capacitor is charged to a predetermined potential. (2) The copying apparatus according to claim 1, wherein the first set temperature and the second set temperature are the same. (3) Claims 1 or 2 are characterized in that the energization of the platen plate heater and the charging of the main capacitor are controlled so that they do not occur at the same time.
Copying device as described in Section. (4) Control is performed so that charging of the main capacitor after reaching the first set temperature is performed with priority over heating of the platen plate, as set forth in claim 3. Copying equipment.