JPS5990B2 - How to detect malfunction of cut filter for color printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting malfunction of a printing light cut filter (hereinafter referred to as "cut filter") of a color printer and issuing an alarm signal.

Conventionally, as a method to prevent print loss due to malfunction of the cut filter of a color printer, a micro switch or a
A method is known in which a photoelectric switch is used to detect this and, if it is not detected, an alarm is issued. However, this method did not necessarily yield satisfactory results.

In other words, microswitches are not durable and there is a risk of them malfunctioning, photoelectric switches are durable but cannot detect damage to the filter, and it is difficult to install these detectors inside the cut filter unit. is difficult, etc. The present invention eliminates the above-mentioned drawbacks of the conventional cut filter malfunction detection method, and provides a method for eliminating print loss by reliably detecting cut filter damage or malfunction, and issuing an alarm signal. The purpose is to

The object of the present invention is to provide a method for detecting a malfunction of a cut filter of a color printer.
When a certain color of light is cut, the signal obtained by logarithmically converting the output of the receiver of that color and the signal of the receiver before this is cut. This is achieved by comparing the output with a logarithmically transformed signal and determining that the cut filter is malfunctioning if the difference is smaller than a preset value even for negative colors. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic side view of essential parts of a color printer showing one embodiment of the present invention.

FIG. 2 shows a method for producing a signal indicating that the cut filter is operating normally in the color printer shown in FIG. 1. FIG. 3 shows a method of using this signal to generate a signal indicating that the operation of the cut filter is abnormal, and FIG. 4 is a time chart thereof. Generally, the most noticeable effect when a cut filter is malfunctioning is that when the cut filter solenoid is energized, that color of light is not cut out.

To detect whether the light of that color has been cut, place a light receiver equipped with a filter of the complementary color of that color on the exit side of the light of the cut filter, and detect that the light is attenuated. good. Two problems arise here. One is that a receiver is required to detect the attenuation of light for the three colors, and the other is that the amount of attenuation of that color by the cut filter is determined depending on whether the negative is over or under. Since the absolute values are different, detection based on the amount of change is not possible.

Regarding the former, if the printer has a cut filter on the negative side of the photoreceiver, the photoreceiver that detects the amount of red, green, and blue (hereinafter referred to as R, .G.B.) that the printer itself inherently has will be used. If used, no additional materials are required.

The latter problem can be solved by performing density conversion, that is, logarithmic conversion, of the amount of received light. This will be explained with reference to FIG. 5, which shows a time chart and waveforms. black shutter,
Cyan cut filter C1 Magenta cut filter M
, yellow cut filter Y operates as shown in FIG. 5, then the output of the red light amount detector changes as shown in the amount of R light received. At this time, if the negative is an under-negative, when the C filter operates, the amount of R light received will be greatly attenuated (point 1 in Figure 5).Conversely, if there is no attenuation, the C filter will be It is sufficient to issue an abnormality alarm assuming that it is not working. However, in the case of an overnegative image, even if the C filter operates, the amount of attenuation of the amount of R light received is small. However, the rate of attenuation is the same (point 2 in Figure 5)
. In comparison, the density-converted signal increases significantly when the C cut filter operates. This increment is always =
It is fixed. Therefore, as a method for detecting abnormality in the operation of the C filter, it is sufficient to detect whether or not there is a change in the C concentration. In other words, the signal Bl, b2 is the logarithmically converted signal of the R light receiver output when the R (red) light is cut by the cut filter C, and the logarithmically transformed signal of the light receiver output before the R light is cut. Al and a2 are compared, and if the differences b1-a1 and B2-A2 are smaller than preset values, it is determined that the cut filter C is malfunctioning. Although only R has been shown above, G. ．． B
The same thing can be said about the colors, and the gist of the present invention is to determine that the cut filter is malfunctioning if even one of these colors is defective. Hereinafter, a more detailed explanation will be given based on a specific example, including a circuit that issues an alarm.

In the embodiment shown in FIG.
B is R. G. There are three colors of B separately, and when cut filters 2C, 2M, and 2Y are inserted, they are affected by them.

A method for detecting that the cut filters 2C, 2M, and 2Y are operating normally will be described below. In FIG. 2, the cut filter is C. M,. Suppose that it is entered in Y(7) order. At this time, the signals obtained by logarithmically converting the amount of received light are 5, 6, and 7. In each case, the density of the complementary color of the cut light changes greatly. For example, looking at C filter operation,
When the C filter operates, the signal number 5 increases significantly, so it is sufficient to calculate this difference and determine that it is abnormal if it is smaller than a preset value, but here, after passing through the differentiation circuit, An example of clipping at a certain level value will be described, and a circuit that issues an alarm will be explained. When the C filter is activated, the C concentration signal increases rapidly, so when it is passed through a differentiating circuit with a certain time constant, it becomes 8
become that way. If you grip this at a certain level and shape the waveform, you will get a waveform like 9. This is because when cut filter C is activated, a pulse-like waveform is generated.
In addition, it always appears when the amount of light received changes significantly, so
In order to ensure detection, it is ANDed with a waveform like O so that it becomes 8, so that it becomes effective only when the cut filter of C starts to be energized. [Phase] is the output of a timer that operates when the cut filter of C starts to be energized. The waveform D thus obtained is generated every time the cut filter C operates normally. Since this does not occur when there is an abnormality, the alarm can be issued only when this ◎ pulse is not generated. To achieve this, set the flip-flop with the ◎ pulse. Its output waveform is @. This flip-flop (F.F.) is connected to CF. F. This kind of thing is called M. Y signals are also created, and each MF. F. , Y.F.
F. Name it. These CF. F. , M.F. F. , Y.F.
．． F. is a memory that each filter has operated normally. A method for producing a signal indicating that the filter is malfunctioning from these output signals is shown in FIG. ANDl in Figure 3 is C
FFlMFF,. Since the outputs of each YFF are ANDed, the output becomes a signal indicating that all cut filters have operated normally. This signal then activates the timer. This state can be seen by looking at the relationship up to @ in Figure 4. If the cut filter is not activated for even one color, no output will be output from this timer. The right part of FIG. 4 shows the case where the cut filter C is abnormal. The signal 9 obtained by inverting the output of this timer and the pulse 5 which is generated at the end of exposure are ANDed by AND2, and this output is indicated by @. When a pulse appears on O,
This indicates that some cut filter has malfunctioned, and this pulse can be input to the F/F as an alarm signal, and its output can be used to indicate [Yes]. Further, the timer falling differential pulse signal of O can be used as a confirmation pulse that the filter has operated normally, and can also be used as a start signal for the next process.
As mentioned above, the above method is fine for color printers that have a sequence in which all three cut filters are activated every time, but for printers that have a sequence in which only two cut filters are activated, the first The configurations shown in FIGS. 6 and 7 are effective as a method of issuing an alarm. This creates an AND between a signal indicating that each cut filter is energized and a signal indicating that the cut filter is not actually operating, and if these signals persist for a certain amount of time, an alarm is issued indicating that there is an abnormality. be. This method can be applied to any sequence of printers. Below, based on Figures 6 and 7, we will briefly explain a reference example of a mechanism for generating an alarm when a malfunction occurs in the M-cut filter when the sequence is such that the Y-cut filter does not operate from the beginning. state This reference example also obtains the @ pulse signal shown in FIG. 2, and CF. F. (MF.F.
) is exactly the same as the example shown earlier, so the explanation will be omitted.

C.F. F. , M.F. F. , if the inverted outputs of YF5F5 are respectively 5, 6, and 7, and the cut filter activation signals are 2, 3, and 4, the output obtained by passing 2 and 5, 3 and 6, and 4 and 7 through an AND circuit is 8. ,9,@. This signal is passed through an 0R circuit to a low-pass filter, and the waveform is shaped into the @ signal, which causes the alarm F. F. Activate the circuit and use it as an alarm signal. That is, when the M-cut filter operates normally, the output 8 of AND1 and the output 9 of AND2 are all short pulses, and when they are passed through a low-pass filter and waveform shaped, the output becomes 0. On the other hand, the M cut filter is abnormal and the MF. F. If no set input is applied to MF., the inverted output MF. F. The output of σ6 is always set, and a slightly long pulse is generated in the AND output 9 of 3 and 6, and since it is not cut by the low-pass filter, a rectangular wave signal is generated in the signal @. Therefore, this signal ◎ causes alarm F. F. All you have to do is set it to issue an alarm. In addition, the configuration of the printer may not be as shown in Figure 1.

In other words, the cut filter is located between the lens and the color roll vapor. In this case, a half mirror or the like is installed between them, and a light receiver for abnormality detection is installed between the three
I have to add color. As explained above, according to the present invention, the following several effects can be obtained.

1. An abnormality in the operation of the cut filter can be detected without performing any processing on the cut filter or its surroundings.

2. In a printer with a so-called optical high correction configuration as shown in FIG. 1, no additional parts are required in the mechanical section.

3. Both solenoid abnormalities and filter cracks can be detected.

4. Color printer cut filters are consumable items, so they will eventually malfunction.

If you print without realizing it at the time, the loss is considerable, but by using this device, that loss can be reduced to almost zero. Note that in a printer that determines the three-color density of a negative and controls exposure based on this, if this density signal is used, a logarithmic conversion means is not necessary.

The receiver is one without three-color separation, and the logarithmic conversion means (
A similar warning can also be issued.

[Brief explanation of drawings]

Fig. 1 is a schematic side view showing the configuration of the main parts of the printer, Fig. 2 is a diagram showing the process of creating a signal indicating that the cut filter has operated normally, and Fig. 3 is a block diagram of the device showing an embodiment of the present invention. 4 is a time chart thereof, FIG. 5 is a diagram explaining the influence of the operation of the cut filter, FIG. 6 is a block diagram of a device showing another embodiment of issuing an alarm according to the present invention, and FIG. This is the time chart. 1... Lamp, 2C, 2M, 2Y...
C. MY cut filters, 3...Mirror box, 4...Diffuser, 5...
...Negative, 6...Luns, 7R, 7G, 7B...
...R. G. Each receiver of B, 8... Shutter, 9... Color vapor.

Claims (1)

[Claims] 1. In a color printer that inserts a cut filter to finish printing exposure using each color light, the light transmitted through the negative film is separated into three colors, and when a certain color light is cut, the receiver output of that color is Compare the logarithmically converted signal and the logarithmically converted signal of the receiver output before it is cut, and if the difference is smaller than a preset value for even one color, it is determined that the cut filter is malfunctioning. A method for detecting malfunction of a cut filter for a color printer, characterized in that: