JPS629974A - Printer - Google Patents

Abstract

PURPOSE:To detect whether recording paper is wound at an accurate position, by mounting a sensor for detecting the side end part of the recording paper on a platen and a discrimination means receiving the output signal from the sensor during a time from the beginning of the winding of the recording paper around a platen to the finish of the winding thereof and discriminating the wound state of the recording paper on the basis of the change in said output signal. CONSTITUTION:When recording paper 1 is accurately wound around a platen 3, the recording paper 1 and the platen 3 are equally contained in an irradiation region 51-1 during a time when the platen 3 is rotated from a predetermined angular position A to a predetermined angular position B. A photodiode 8 as a light receiving means for receiving the reflected light from the irradiation region 51-1 is arranged at the position parallel to a light emitting diode 7. The light emitting diode 7 is connected to a control circuit 6 and the lighting and turning-OFF thereof are controlled by the control circuit 6. The photodiode 8 is also connected to the control circuit 6 and the output signal from the photodiode 8 is processed by the control circuit 6 and the position of the recording paper 1 is judged by this method.

Description

Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to a printer, and more particularly, to a printer in which at least one end of recording paper is fixed to a platen I- by a fixing member, and the platen is rotated relative to the recording paper. This relates to a printer that winds the recording paper around the platen 1- by doing this, and then records on the recording paper of the platen 1- with the recording head.

(Background of the Invention) I-Refer to FIG. 8 for the recording operation of the above-mentioned type of printer, taking a thermal printer as an example.1. I will explain. In this example, a case will be explained in which thermal recording is performed by bringing a thermal head as a recording head into pressure contact with color-forming recording paper.

Referring to FIG. 8, when the recording paper l is conveyed to a fixed position, that is, between the fixed member 2 and the platen 3 by a transport mechanism (not shown), the fixed member 2 is moved to a drive (not shown). Driven by the tJ1 mechanism, one end of the recording paper l is clamped and fixed between it and the platen 3. Next, when the platen 3 starts rotating in the direction of the arrow shown by a drive mechanism (not shown), the recording paper l is wound around the platen 3F. Figure 8 is like this! C; is shown. Then, the platen 3 rotates to a predetermined printing start position, and the recording head 4 is rotated by a drive mechanism (not shown).
Then, the recording paper 1 is held between the platen 3 and the recording head 4 and they come into contact with each other. After that, a print signal is sent from a control circuit (not shown) to the recording head 4, and in response, the heating elements arranged in a line that make up the recording head 4 generate heat, and the recording paper l develops color to form one line. The minutes will be printed. When one line of printing is completed, the platen 3 rotates by a small angle in the direction of the arrow to execute the next printing, and from then on, the necessary]
The heat generation of the recording head 4 and the rotation of the platen 3 are repeated until printing of the image is completed.

Referring to FIG. 9, if the recording paper l is wrapped in one line around both end surfaces of the platen 3, the recording area 50 defined by the recording head 4 will be wrapped around the recording paper l as shown in the figure. to the correct position.

However, if the recording paper l is not parallel to both end surfaces of the platen 3 and is wrapped tightly around the platen 3, the recording area 50 becomes oblique to the recording paper l, as shown in FIG. It feels strange to the viewer. Also, the first
The recording paper 1 is placed on the platen 3 more diagonally than the position shown in figure 0.
If the recording paper 1 is wrapped around the recording paper 1, it will not only protrude from the platen 3 and cause various mechanical parts of the printer to malfunction, but if the printing area 50 protrudes from the recording paper 1, the platen 3 will be directly heated by the recording head 4. Therefore, there is a risk that the surface of the platen 3 may be burned out.

(Objective of the Invention) An object of the present invention is to provide a printer that detects whether or not the recording paper is wound at the wrong position while winding the recording paper around the platen.

(Summary of the Invention) The present invention is applied to a printer that wraps a recording paper around a platen and records on the recording paper I- by a recording hend, and the printer includes a platen 1. It has a sensor that detects the side edge of the recording paper. and a discrimination means that receives an output signal from the sensor from when the recording paper starts winding around the platen until it ends, and discriminates the winding state of the recording paper based on a change in the output signal. do.

As the sensor, for example, a pair of light emitting means and light receiving means can be used. In this case, it is necessary to change the reflectance of the recording paper and the reflectance of the platen.

The discrimination means can detect the wrapping state of the recording paper by comparing, differentiating, or integrating the outputs from the sensors.

(Example) First Example - FIG. 1 shows an example of the present invention. The same parts as in FIG. 8 will be described with the same reference numerals 4=t.

A flat part 3a for fixing the recording paper l is provided on the outer peripheral surface of the platen 3, and a bar 2, which is a fixing member, is provided on the flat part 3a. When the fed recording paper l reaches a predetermined position, the 8-2 is driven to create a gap between the bar 2 and the f-plane portion 3a, and the leading end of the recording paper l enters the gap, and then, Recording paper 1 is placed between the bar 2 and the f-plane portion 3a.
is configured so that it is held between the two. The platen 3 is driven by a platen drive motor 5, and after the recording paper 1 is held between the bars 2, the motor 5 is driven by a command from the control circuit 6, whereby the platen 3 rotates in the direction of the arrow and the recording paper 1 is It can be wrapped around platen 3. A step motor can be used as the platen drive motor 5.

A light emitting diode 7 as a light emitting means is provided at a position facing the vicinity of the side end of the recording paper 1 when the recording paper 1 is normally wound around the platen 3. Light emitting diode 7
As shown in FIG. 4(a), the output light emitted from
With the spread of the irradiation area 51-1, the recording paper l and the platen 3-1- are irradiated. In this example, when the recording paper l is wrapped around the platen 3 by 1F, the irradiation area is The recording paper 1 and the platen 3 are equally contained therein.

At a position lined up with the light emitting diode 7, an irradiation area 51-1 is provided.
A photodiode 8 is disposed as a light receiving means for receiving reflected light from. The light emitting diode 7 is connected to a control circuit 6, and is controlled to turn on and off by the control circuit 6. The photodiode 8 is also connected to the control circuit 6, and the output signal from the photodiode 8 is processed by the control circuit 6, thereby determining the position of the recording paper l. In this example, the reflectance of the platen 3 is 10
The output voltage of the photodiode 8 when the recording paper 1-1- is irradiated with the light emitted from the light emitting diode 7 is smaller than the reflectance, and the output voltage of the photodiode 8 is larger than that when the light emitted from the light emitting diode 7 is irradiated onto the platen 3. It is being done. The pair of light emitting means and light receiving means constitute a sensor for detecting the position of the recording paper 1. Furthermore, a phototransistor may be used as the light receiving means.

As shown in FIG. 2, the control circuit 6 includes a sensor amplifier 60 that amplifies the signal from the photodiode 8, a sampling circuit 61 that samples the output of the sensor amplifier 60 at a predetermined timing, and is supplied with the output of the sampling circuit 61. and a calculation circuit 62 for determining whether the position of the recording paper 1 is normal or not, a central control circuit 63 connected to the calculation circuit 62, and a motor drive circuit 64 controlled by the central control circuit 63. ing. A timing signal determined to be output at a predetermined angular position of the platen 3 is supplied to the sampling circuit 61 and the arithmetic circuit 62 from the motor drive circuit 64. Further, the platen drive motor 5 is controlled by the motor drive circuit 64. For example, a rotary encoder can be used to detect the angle of the platen 3. Furthermore, when a step motor is used, the angular position of the platen may be detected based on the number of steps.

A detailed circuit of the arithmetic circuit 62 will be explained with reference to FIG.

The arithmetic circuit 62 has a timing pulse generation circuit 62a. This timing pulse generation circuit 62a is connected to a motor drive circuit 64, and is connected to a predetermined angular position A of the platen 3.
A timing signal Sa is output at a position B, which is further rotated from an angular position A, and a timing signal sb is output at a position B further rotated from the angular position A. Also,
A sample hold circuit 62b receives the timing signal Sa from the timing pulse generation circuit 62a, samples and holds the incoming signal at that time, and an output signal from the sampling circuit 61 is supplied to one terminal, and the other terminal is supplied with the output signal from the sampling circuit 61. A comparator 62c is supplied with the output of the sample-and-hold circuit 62b, and a sample-and-hold circuit 62d is supplied with the output of the comparator 62c.

This sample hold circuit 62d is connected to the timing pulse generation circuit 62a, and is arranged so that the timing signal sb is combined.

Referring to FIG. 4(a) and FIG. 5(a), reference numeral 5
The irradiation area indicated by 1-1 is the light emitting diode 7 when the platen 3 starts to rotate and the recording paper l starts to wrap around.
51-2 indicates the position of the irradiation area when the winding is completed. That is,
Rotating the platen 3 relative to the fixed pair of light emitting means 7 and light receiving stage 8 is equivalent to scanning 17 the sensors 7 and 8 in the direction of the arrow along the vicinity of the side edge of the recording paper 1. Therefore, the irradiation start position can be set at mm 51-1, and the irradiation end position can be set at 51-2.

As shown in FIG. 4(a), the recording paper 1 is placed on the platen 3.
If it is wrapped around the cloth, it will follow the rotation of platen 3.
The output 'i1 [pressure] of the photodiode 8 becomes as shown in FIG. 4(b).

That is, when the irradiation area 51-1 passes through the bar 2 and begins to detect the recording paper 1, the reflection on the surface of the platen 3 (because the reflectance of the surface of the recording paper 1 is high, the output of the photoI diode 8 The voltage starts at 1 JfL.When the platen 3 rotates to the predetermined angular position IW, that is, the irradiation area 51-
When the photodiode 1 passes through the bar 2 and evenly overlaps the recording paper l and the platen 3, the output voltage of the photodiode 8 becomes maximum, and this state continues for a while. When the platen 3 further rotates to a predetermined angular position B, that is, when the end of the recording paper l comes to be included in the irradiation area, the proportion of the recording paper 1 in the irradiation area decreases,・
The output voltage of diode 8 begins to decrease. When the irradiation area reaches the position indicated by reference numeral 51-2, the recording paper l is no longer included in the irradiation area, so the output voltage of the photodiode 8 becomes smaller.

Therefore, if the timing signals Sa and sb from the timing pulse generation circuit 62a are outputted at the positions A and B shown in FIG. 4(b), first, the timing signal S
At timing a, the output signal from the sensor amplifier 60, that is, the output signal from the photodiode 8, is sampled by the sampling circuit 61 and supplied to the comparator 62c. Since the timing signal Sa is also supplied to the sample hold circuit 62b, the angular position A of the platen 3
The sensor detection voltage at sample and hold circuit 62b
sampled and retained.

Next, when the platen 3 rotates to a predetermined angular position B,
Timing signal s from timing pulse generation circuit 62a
b is supplied to a sampling circuit 61, whereby the output signal of the diode 8 at angular position B is sampled and supplied to a comparator 62c. Therefore, the angle 1 held in the sample and hold circuit 62b
(2) The sensor detection voltage at position A and the sensor detection/output voltage at angular position B are compared, and a signal indicating the comparison result is supplied to the sample and hold circuit 62d. Since the timing signal sb is supplied from the timing pulse generation circuit 62a to this sample hold circuit 62d,
Comparator 6 at the timing of generation of timing signal sb.
2c comparison signal is sampled and held.

If the recording paper l is correctly wrapped around the platen 3 as shown in FIG. 4(a), the output voltage of the photodiode 8 will be as shown in FIG. The comparison signal indicates that the voltage values of the two are equal, and the result is the sample bold circuit 6.
It will be held at 2d.

On the other hand, as shown in FIG. 5(a), the recording paper 1 is placed on the platen 3.
If the platen 3 is wrapped obliquely to the angular position A, the area of the platen 3 included in the irradiation area gradually increases while the platen 3 rotates from angular position A to angular position B, so that the output from the photodiode 8 The waveform of the signal becomes as shown in FIG. 5(b). Therefore, at the angular position B, the two input voltages of the comparator 62c are different, and a comparison signal indicating that the recording paper l is bent and wound around the platen 3 is cleared from the comparator 62c, and this result is used as the sample. It is held by a hold circuit 62d.

The central control circuit 63 receives the output signal of the sample hold circuit 62d and stops the motor when the recording paper l is tilted.
1 signal is output to the motor drive circuit 64 to immediately stop the rotation of the platen 3. At the same time, the recording head 4
It is preferable to also reduce the power of the print signal to the. It is also possible to notify the operator using a buzzer, etc. In this case, the operator removes the recording paper and then performs the IIJ I&-- series operation.

-Second Embodiment- With reference to FIG. 6, the second embodiment of the present invention will be described with reference to 1-), but since everything except the arithmetic circuit 62 is the same, only the arithmetic circuit 62 will be explained.

The arithmetic circuit 62 in the second embodiment is configured such that the platen 3 is
] Angle 4 between the angular positions A and B mentioned above: I-C (A≦
A timing pulse generation circuit 62a that outputs a timing signal sb when C≦B), and a sampling circuit 6
A differentiating circuit 62e to which an output signal of 1 is supplied, and a window comparator 62 to which the outputs of the differentiating circuit 62e are combined.
f, and a sample hold circuit 62d to which a comparison signal from a window comparator 62f is supplied and a timing signal Sc from a timing pulse generation circuit 62a is supplied. Here, the output of the differentiating circuit 62e is detected by the window comparator 62f, and when the output exceeds the range of 0:tdV, the output signal of the window comparator 62f is inverted.

When the output value t'f from the photodiode 8 as shown in FIG. 62f is detected to be within the range of 0±dV, indicating that the recording paper is in the normal position.

- On the other hand, when the output material V 71 as shown in FIG. 5(b) is output from the photodiode 8, sampling 1 at the timing signal; Sc! ] It is detected by the window comparator 62f that the output voltage of the photodiode 8 sampled by the path 61 is outside the range of O±dV, indicating that the recording paper is tilted and wrapped around the platen 3.

- Third Embodiment A third embodiment of the present invention will be described with reference to FIG. In this example, the sampling circuit 61 is omitted, and the output of the sensor amplifier 60 is integrated over the angular position A to B.
The inclination of the recording paper l is detected based on the 6-minute value.

That is, the arithmetic circuit 62 in the third embodiment outputs the timing signal 4Sa when the platen 3 comes to the 1-mentioned angular position A, and outputs the timing signal 4Sa when the platen 3 comes to the 1-mentioned angular position. A timing pulse generation circuit 62a that outputs the timing signal Sb, and an integration circuit 62g that is directly connected to the sensor amplifier 6o and integrates the 111 force signal.
and the output of the integrating circuit 62g is supplied to one end r-,
A comparator 62c to which a quasi-voltage from the reference voltage source 62i is supplied to the other end -f, and a comparator 62c
The sample and hold circuit 62d is supplied with a comparison signal from the timing pulse generation circuit 62a and a timing signal sb from the timing pulse generation circuit 62a. Here, the integration circuit 62g is connected to the timing pulse generation circuit 62a, and is configured to start integration at the timing of the timing signal Sa and stop the integration operation at the timing of the timing signal sb. Then, the reference voltage value of the reference voltage source 62i is appropriately determined based on the integrated value of the integrating circuit 62g when an output signal as shown in FIG. 4(b) is obtained from the photodiode 8.

When an output signal as shown in FIG. 4(b) is obtained from the photodiode 8, the comparison signal from the comparator 62c indicates that the recording paper has been wound around the platen 3 normally.

On the other hand, when an output signal as shown in FIG. 5(b) is obtained from the photodiode 8, the integrated value obtained from the integrating circuit 62g is smaller than the reference voltage value obtained from the reference voltage source 621, so the comparator 62c The comparison signal obtained from this indicates that the recording paper is tilted and wrapped around the platen 3.

Although the explanation has been given below using thermal recording as an example, the present invention is not limited to thermal recording printers, but can also be applied to printers in which recording paper is wound around a platen and a recording head performs recording, for example, It can be applied to any device such as an inkjet printer.

Furthermore, although the case where the recording paper is rectangular has been described above, it can also be used for recording paper of a special shape. In other words, if the recording paper is always wrapped around +E, the waveform of the sensor output signal V'i depends on the physical properties of the recording paper, including its shape and size, and the waveform cannot be known in advance. Therefore, by comparing the normal output voltage and the actual output voltage, it is possible to handle even special shapes of recording paper. Furthermore, damage or staining of the recording paper can also be detected from this.

(Effects of the Invention) As explained above, according to the present invention, there is a sensor that detects the side edge of the recording paper on the platen-1, and a sensor that detects the side edge of the recording paper on the platen. Discrimination means is provided which receives the 111 force signal from the sensor and, based on the change in the output signal, discriminates whether the recording paper is wrapped around the platen. Therefore, if it is found from the detection result that the recording paper is tilted, it is possible to notify the operator or stop printing, thereby preventing printer failure. In addition to eliminating the cause of this, burnout of the platen can also be prevented.

Furthermore, by distinguishing the condition of the recording paper from changes in the detection signal of the sensor as in the present invention, it is also possible to detect damage or staining of the recording paper.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of its control circuit, and FIG. 3 is a circuit diagram showing an example of the operation P'11 path shown in FIG. , Figure 4(a)
5(a) shows the position of the recording paper and the irradiation area of the opening light emitted from the light emitting means. 41Δ(b) and FIG. 5(b) show the output signal from the light receiving-L stage. The graphs shown in FIGS. 6 and 7 show the second embodiment of the present invention. FIG. 8 is a perspective view showing the area around the platen of a conventional printer, and FIGS. 9 and 10 are diagrams for explaining the relationship between the desired recording area and the recording paper. be. 1: Recording paper 2: 8-3 Nibraten 4: Recording head 5 Nibraten drive motor 6: Control circuit 7: Light emitting diode (light emitting means) 8: Photo diode (light receiving means) 61: Sample hold circuit 62: Arithmetic circuit 62a: Timing pulse generation circuit 62b = sample hold circuit 62c: comparator 62d: sample hold circuit 62e: differentiating circuit 82f, 62i: reference voltage source 62g: integrating circuit Applicant: 11 Honkogaku Kogyo Co., Ltd., agent and patent attorney
Fuyu Nagai Kikume “10 Ward Z 5θ Figure 9 fθ diagram

Claims (1)

[Scope of Claims] 1) In a printer in which a recording paper is wound around a platen and a recording head records on the recording paper, there is provided a sensor that detects the side edge of the recording paper on the platen, and a sensor that detects the side edge of the recording paper on the platen. 1. A printer comprising: a discriminating means for receiving an output signal from the sensor between the start of wrapping and the end of wrapping, and discriminating the wrapping state of the recording paper based on a change in the output signal. 2) The discrimination means has a comparison means, and compares the magnitude of at least two points of the output signal from the sensor, and when the two are equal, it is determined that the position of the recording paper is normal. A printer according to claim 1. 3) The discrimination means has a differentiation means, and the differentiation means outputs a differential signal according to the rate of change of the output signal from the sensor, and determines whether or not the position of the recording paper is normal based on the differential signal. Claim 1 characterized in that
Printers listed in section. 4) The discrimination means has an integration means, and the integration means outputs an integral signal corresponding to the integral value of the output signal from the sensor that continuously enters, and the position of the recording paper is determined to be normal by the integral signal. 2. The printer according to claim 1, wherein the printer determines whether or not the printer is a printer. 5) The sensor includes a pair of light emitting means and light receiving means, and is configured such that the light emitting means illuminates the vicinity of a side edge of the recording paper, and the light receiving means receives the reflected light. A printer according to claim 1. 6) The light emitting means is a light emitting diode whose intensity distribution of emitted light converges in a certain direction, and the light receiving means has a sensitivity distribution which converges in a certain direction and whose photosensitive wavelength band is the same as that of the light emitting diode. 6. The printer according to claim 5, wherein the printer is a phototransistor or a photodiode that includes at least a light emission wavelength band.