JP2892365B2 - Image recording device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image recording apparatus.

2. Description of the Related Art An image recording apparatus that records an image on a thermosensitive recording paper using a thermal head is often used in a recording unit of a facsimile apparatus, a small printer, and the like.

In such an image recording apparatus, when recording an image one line at a time, of the heating elements corresponding to each pixel of the thermal head, a pulse is applied to the heating element corresponding to a black pixel.
Also, when energizing this heating element, the temperature of the thermal head is detected, and when the temperature is low, the pulse width of the energizing pulse is widened, and when the temperature is high, the pulse width is narrowed, A predetermined thermal energy is supplied to the recording paper so as to obtain a recording image having a constant density.

[Problems to be Solved by the Invention] The temperature of the thermal head is detected by a temperature detecting element such as a thermistor to which the thermal head is attached. However, until the temperature of the heat generating portion of the thermal head fluctuates and thereby the temperature of the temperature detecting element changes,
There is some delay.

Therefore, for example, when a specific line is recorded,
Sudden temperature changes such that a large thermal energy is generated in the thermal head and the image density is increased only in that line,
Not detected by the temperature detection element. Therefore, in this case,
An unnatural recording image in which the density of only a specific line is high is output.

As described above, in the related art, since a temporary rise in the temperature of the heat generating portion of the thermal head has not been detected, there has been a problem that an image having an unnatural image density is output as it is.

On the other hand, during image recording, if a paper jam occurs in the recording paper conveyance path or the conveyance mechanism breaks down, the movement of the recording paper may stop.

However, in the related art, since the conveyance state of the recording paper has not been detected, the recording operation is performed as it is even when the recording paper stops. For this reason, there is a problem that the recording operation is useless, and in the case of a paper jam, the paper jam state is further deteriorated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image recording apparatus which solves the above problems, prevents the output of an image having an unnatural density, and eliminates the unnecessary recording operation.

Means for Solving the Problems The present invention relates to an image recording apparatus for recording image information on recording paper using a thermal recording head, and a speed detecting means for detecting a recording speed in a sub-scanning direction during image recording. Power amount determining means for determining an upper limit of the amount of power supplied to the thermal recording head according to the recording speed detected by the speed detecting means,
Power amount calculating means for calculating the amount of power supplied to the thermal recording head every time image information is recorded; and the power amount calculated by the power amount calculating means is an upper limit of the power amount determined by the power amount determining means. Recording stop means for stopping the recording operation of the image information when the number exceeds the limit.

In an image recording apparatus that records image information on recording paper using a thermal recording head, a speed detecting unit that detects a recording speed in a sub-scanning direction during image recording, and a recording speed detected by the speed detecting unit. Power amount determining means for determining the upper limit of the amount of power supplied to the thermal recording head during one-line recording, and power for calculating the amount of power supplied to the thermal recording head every time one line of image information is recorded. Power calculation means, and recording stop means for stopping a recording operation of image information when the power amount calculated by the power amount calculation means exceeds an upper limit of the power amount determined by the power amount determination means. Things.

In an image recording apparatus that records image information on recording paper using a thermal recording head, a speed detecting unit that detects a recording speed in a sub-scanning direction during image recording, and a recording speed detected by the speed detecting unit. Power amount determining means for determining an upper limit of the amount of power supplied to the thermal recording head in accordance therewith, power amount calculating means for calculating the amount of power supplied to the thermal recording head each time image information is recorded, and the power amount A recording stop unit for stopping the image information recording operation when the power amount calculated by the calculation unit exceeds the upper limit of the power amount determined by the power amount determination unit; and a recording operation stopped by the recording stop unit. Then, a recording restart means for restarting the recording operation when the stop time exceeds a predetermined time is provided.

In an image recording apparatus that records image information on recording paper using a thermal recording head, a speed detecting unit that detects a recording speed in a sub-scanning direction during image recording, and a recording speed detected by the speed detecting unit. Power amount determining means for determining an upper limit of the amount of power supplied to the thermal recording head in accordance therewith, power amount calculating means for calculating the amount of power supplied to the thermal recording head each time image information is recorded, and the power amount Recording of image information when the power amount calculated by the calculation unit exceeds the upper limit of the power amount determined by the power amount determination unit, or when the recording speed detected by the speed detection unit is smaller than a predetermined value. Recording stop means for stopping the operation.

[Operation] By calculating the amount of electric power supplied to the heat generating portion of the thermal head, a temporary rise in the temperature of the heat generating portion of the thermal head can be predicted. Therefore, when the supplied power amount exceeds the specific limited power amount, by stopping the recording operation, it is possible to prevent an unnatural image having a partially high density from being output as it is.

By the way, for example, when the moving speed of the recording paper is high, the recording density of the image becomes low even if the amount of heat generated by the thermal head is constant. Therefore, by determining the above-mentioned limited electric energy according to the moving speed of the recording paper, it is possible to more correctly determine that the density of the recorded image has reached a certain density or more.

Further, when the moving speed of the recording paper is not constant, the recording operation is stopped, so that unnecessary recording operation when a paper jam of the recording paper or the transport mechanism breaks down can be eliminated.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a facsimile apparatus according to an embodiment of the present invention. In the figure, a scanner 1 reads a document image to extract image information of a predetermined resolution, and a plotter 2 records the image information on a recording paper. The encoding / decoding unit 3 encodes image information to be transmitted and decodes received image information. The image memory 4 temporarily stores image information to be transmitted and received.

The network control device 5 performs predetermined calling and receiving operations by capturing a line, transmitting a selection signal as a destination telephone number, detecting an incoming call, and the like.

The modem 6 modulates and demodulates the image information and transmits the same, and also transmits various procedure signals in the transmission control procedure. The communication control section 7 controls the network control device 5 and the modem 6 to execute facsimile transmission according to a predetermined transmission control procedure.

The operation display unit 8 displays the status of the apparatus and allows the operator to perform various operations. System control unit 9
Is constituted by a microcomputer system, and controls the above-mentioned units to execute a predetermined operation of the facsimile apparatus.

FIG. 2 shows a schematic configuration of the plotter 2, and a thermal recording paper 13 is pressed against a thermal head 11 by a platen roller 12. One end of the shaft of the platen roller 12 is driven by a driving device 14 including a step motor and gears, and a circular slit plate 15 having radial slits is fixed to the other end.

At the edge of the slit plate 15, a photo-interrupter 16 for detecting rotation of the slit plate 15 based on light transmitted to the slit is attached. In addition, a photosensor 17 including a light emitting element and a light receiving element is mounted on a transport path of the thermal recording paper 13. The photosensor 17 irradiates recording paper with light and extracts a change in the reflected light by an analog signal.

FIG. 3 is a block diagram showing a part of the plotter 2 and a system control unit 9 for controlling the plotter 2. In the figure, a detection signal of a photo interrupter 16 is input to a CPU 201 provided in a system control unit 9, and a detection signal of a photo sensor 17 is input to a moving speed detection circuit 20.
Entered in 2. The moving speed detecting circuit 202 detects the moving speed of the thermal recording paper 13 based on the detection signal of the photo sensor 17, and the detected moving speed information is input to the CPU 201.

The thermistor 203 is fixed to the thermal head 11 to detect the temperature, and the detection signal is transmitted through an A / D (analog / digital conversion circuit) 204.
Input to CPU201.

The recording control circuit 205, based on the control information of the CPU 201,
An image signal transferred line by line is input, and the thermal head 11 is driven to record an image. The step motor drive circuit 206 drives the step motor 207 in the drive device 14 to convey the thermal recording paper 13 in the sub-scanning direction. The power supply for operating the recording control circuit 205, the thermal head 11, the step motor drive circuit 206, and the step motor 207 is turned on and off by a switch circuit 208.

The image signal is input to an integration circuit 209 that integrates the signal for each line. In the integrating circuit 209, the input image signal is input to the inverting input terminal of the operational amplifier 209b via the resistor 209a. The ratio inverting input terminal of the operational amplifier 209b is grounded. A capacitor 20 is connected between the inverting input terminal and the output terminal of the operational amplifier 209b.
9c and the analog switch 209d are connected.

The output of the integration circuit 209 is input to the A / D 210, and the A / D 21
The output of 0 is input to the CPU 201.

With the above configuration, the facsimile apparatus of the present embodiment has a memory receiving function. That is, when the operator sets “memory reception” by a predetermined operation of the operation display unit 8, the facsimile apparatus stores the received and received image in the image memory 4 as shown in FIG. It is temporarily stored (process 301).

When recording the received image, the operator performs a predetermined recording start operation. When this recording start operation is performed (Y in process 302), the CPU 201 starts a recording control operation,
First, a variable N for counting the number of interruptions of the recording operation is set to N.
= 0 (process 303).

By the way, when recording an image, the heating element of the thermal head 11 is energized by a pulse.
The temperature of 11 is detected, and when the temperature is low, the pulse width of the energizing pulse is widened, and when the temperature is high, the pulse width is narrowed to supply predetermined heat energy to the recording paper,
A recording image of a constant density is obtained.

For this purpose, next, the CPU 201 detects the temperature of the thermal head 11 by the thermistor 203 and instructs the recording control circuit 205 of the pulse width t of the energizing pulse according to the detected temperature. Here, the step motor drive circuit 206 is operated.

Normally, the switch circuit 208 is turned on, and the recording control circuit 205, the thermal head 11, the step motor drive circuit 2
Operation power is supplied to 06 and 207. The recording control circuit 205 reads out one line of the image signal from the image memory 4 and drives the thermal head 11 with an energizing pulse having a pulse width t specified by the CPU 201.

As a result, an image of one line is recorded on the thermosensitive recording paper 13, and the thermosensitive recording paper 13 is conveyed by one line in the sub-scanning direction by the stepping motor 207, and a one-line recording operation is executed (process 304). .

On the other hand, the CPU 201 sends the image signal of each line to the recording control circuit 20.
Immediately before input to 5, the analog switch 209d is closed to discharge the electric charge of the capacitor 209c. And
The integration circuit 209 integrates the image signal of one line. This image signal is a signal which becomes a high level when the recorded image is a black pixel, and is obtained from the integration circuit 209 by the above integration operation.
A voltage v proportional to the number of black pixels in one line is output.

Next, the CPU 201 determines whether the current line is the last line (step 30).
5) If it is not the last line (N in step 305), the product of the voltage v and the pulse width t instructed to the recording control circuit 205,
That is, the amount of power supplied to the heating element of the thermal head 11 is calculated (step 306). In this case, the electric energy is correctly represented by the product of voltage, current, and time. However, when the resistance value of each heating element of the thermal head 11 is almost constant and does not change, the applied voltage of each element and time That is, it can be expressed by the product of the pulse width. Furthermore, if the applied voltage is constant, the electric energy can be calculated only by the pulse width.

On the other hand, in the CPU 201, an initial value of a limited power amount which is an allowable value of the amount of power supplied to the heating element of the thermal head 11 is set in advance. The CPU 201 compares the limited power amount with the calculated power amount (process 307). Then, when the calculated electric energy is equal to or less than the limited electric energy (Y in step 307), the moving state of the thermosensitive recording paper 13 is determined next.

That is, first, for failure diagnosis of the driving device 14, it is checked whether the detection signal of the photo interrupter 16 has changed, and the rotation state of the platen roller 12 is determined.

By the way, the surface of the thermosensitive recording paper 13 has minute irregularities like ordinary paper, and the intensity of the reflected light of the light irradiated by the photo sensor 17 fluctuates in proportion to the moving speed of the thermosensitive recording paper 13. I do. The light receiving element of the photo sensor 17 outputs a detection signal according to the intensity of the reflected light. Moving speed detection circuit 202
Detects the moving speed of the thermosensitive recording paper 13 based on the fluctuation of the detection signal and outputs it to the CPU 201 (the processing 30
8).

Next, the CPU 201 reads the moving speed and determines whether or not the moving speed is the predetermined speed (step 309). The reason why both the photo interrupter 16 and the photo sensor 17 are checked is to discriminate a failure of the driving device 14 and a paper jam of the recording paper.

By the way, for example, when the moving speed of the thermosensitive recording paper 13 is high, the recording density of an image is low even if the amount of heat generated by the thermal head 11 is constant. Therefore, if the thermal recording paper 13 is properly transported (Y in step 309), a constant proportional to the moving speed of the thermal recording paper 13 is used to determine whether the density of the recorded image is equal to or higher than the predetermined density. Is determined (processing 310).

The above operation is repeatedly performed for each line of the image signal (to process 304). Then, when recording is performed up to the last line (Y in step 305), the above operation is terminated.

Further, during the recording operation, when the amount of power supplied to the thermal head 11 exceeds the limited amount of power (N in process 307), the switch circuit 208 is immediately turned off (process 311).
Then, the variable N is compared with a preset fixed number X (step 311), and when the variable N is equal to or smaller than the fixed number X (step 311).
11Y), an indication that the recording operation has been stopped is displayed (step 313), and the operation is stopped for a fixed time of, for example, 3 minutes (step 314).

If the temperature of the thermal head 11 has risen, heat is radiated during this fixed time and the temperature falls.

After the elapse of the predetermined time, the control state is initialized (step 315), and the variable N is incremented by one (step 31) in order to record again from the first line of the same page.
6), the recording operation of each line is restarted (process 304)
What). As a result, an image of one page is recorded from the beginning.

If the amount of power supplied to the thermal head 11 during the recording operation exceeds the limited power amount, the operation is stopped for a certain period of time and then restarted, as described above. In this case, when the number of stops exceeds a certain number X (N in processing 312), a recording error is displayed (processing 317), and an operator call is made by outputting an alarm sound or the like (processing 317), and the operation is performed. Abort.

On the other hand, if the drive device 14 fails or a paper jam occurs in the thermal recording paper 13, the movement of the thermal recording paper 13 stops. In this case (N in process 309), the switch circuit 208 is turned off (process 319), and an error display indicating a failure of the drive device 14 or a paper jam is performed (process 317).
An operator call is made (process 318), and the operation is stopped.

As described above, in the present embodiment, the temporary increase in the temperature of the heat generating portion of the thermal head 11 is predicted without actually measuring it by calculating the amount of power supplied to the heat generating portion of the thermal head 11. Then, when the supplied power exceeds the set limit power, the recording operation is stopped, so that it is possible to prevent an image having unnatural density from being output as it is. Also, in this case, since the above-mentioned limited electric energy is determined according to the moving speed of the recording paper, it is possible to more correctly determine that the density of the recorded image has become equal to or higher than the predetermined density.

Further, when the moving speed of the recording paper is not the predetermined speed,
Since the recording operation is stopped, it is possible to eliminate a useless recording operation in the case where a recording sheet is jammed or the transport mechanism is broken.

In the above embodiment, the ratio of the black pixels in one line is obtained by integrating the image signal. However, the number of bits indicating the black pixels per one line of image information is counted and obtained. Is also good. In addition, thermal recording paper 13
It is needless to say that the detection of the moving speed is not limited to the optical method such as the photo sensor 17, and other means may be used.

Furthermore, whether or not to stop recording is determined based on the amount of power supplied to the thermal head 11 for each line. However, the determination may be performed based on the average amount of power supplied for a plurality of lines.

Further, the present invention is not limited to a facsimile apparatus, but can be naturally applied to an image recording apparatus using a thermal head.

[Effects of the Invention] As described above, according to the present invention, in an image recording apparatus that records image information on recording paper using a thermal recording head, the recording speed in the sub-scanning direction is detected during image recording. Speed detecting means, power amount determining means for determining an upper limit of the amount of power to be supplied to the thermal recording head according to the recording speed detected by the speed detecting means, and supplying to the thermal recording head every time image information is recorded A power amount calculating means for calculating the calculated power amount, and stopping the image information recording operation when the power amount calculated by the power amount calculating means exceeds an upper limit of the power amount determined by the power amount determining means. Since the recording stop means is provided, an effect is obtained that an image having unnatural density is prevented from being output as it is.

In an image recording apparatus that records image information on recording paper using a thermal recording head, a speed detecting unit that detects a recording speed in a sub-scanning direction during image recording, and a recording speed detected by the speed detecting unit. Power amount determining means for determining the upper limit of the amount of power supplied to the thermal recording head during one-line recording, and power for calculating the amount of power supplied to the thermal recording head every time one line of image information is recorded. Power calculation means, and recording stop means for stopping a recording operation of image information when the power amount calculated by the power amount calculation means exceeds an upper limit of the power amount determined by the power amount determination means. Therefore, it is possible to avoid a situation in which an image having an unnatural density is output for each line.

In an image recording apparatus that records image information on recording paper using a thermal recording head, a speed detecting unit that detects a recording speed in a sub-scanning direction during image recording, and a recording speed detected by the speed detecting unit. Power amount determining means for determining an upper limit of the amount of power supplied to the thermal recording head in accordance therewith, power amount calculating means for calculating the amount of power supplied to the thermal recording head each time image information is recorded, and the power amount A recording stop unit for stopping the image information recording operation when the power amount calculated by the calculation unit exceeds the upper limit of the power amount determined by the power amount determination unit; and a recording operation stopped by the recording stop unit. Then, a recording restart means for restarting the recording operation when the stop time exceeds a predetermined time is provided. Therefore, when the movement of the recording paper is restarted after the stop of the recording paper, the image recording is also restarted and the appropriate recording is performed. Also obtained an effect that it is possible to perform the resume operation.

Further, in an image recording apparatus that records image information on recording paper using a thermal recording head, a speed detecting unit that detects a recording speed in a sub-scanning direction during image recording, and a recording speed detected by the speed detecting unit. Power amount determining means for determining an upper limit of the amount of power supplied to the thermal recording head in accordance therewith, power amount calculating means for calculating the amount of power supplied to the thermal recording head each time image information is recorded, and the power amount Recording of image information when the power amount calculated by the calculation unit exceeds the upper limit of the power amount determined by the power amount determination unit, or when the recording speed detected by the speed detection unit is smaller than a predetermined value. Since the recording stop means for stopping the operation is provided, it is possible to obtain an effect that it is possible to suppress a useless recording operation in the case where a recording sheet is jammed or the transport mechanism breaks down.

[Brief description of the drawings]

FIG. 1 is a block diagram of a facsimile apparatus according to an embodiment of the present invention, FIG. 2 is a schematic diagram of a plotter part, FIG. 3 is a block diagram of a plotter and a part of a system control unit, FIG. The figure is an operation flowchart showing the recording process. 2. Plotter, 9: System control unit, 11: Thermal head, 12: Platen roller, 13: Thermal recording paper, 14: Drive unit, 15: Slit plate, 16: Photo interrupter, 17: Photo sensor, 201: CPU, 202… Moving speed detection circuit, 203…
Thermistor, 204: A / D (analog / digital conversion circuit), 205: Recording control circuit, 206: Step motor drive circuit, 207: Step motor, 208: Switch circuit, 209 ...
Integrator circuit.

Continuation of the front page (56) References JP-A-61-2577 (JP, A) JP-A-63-230362 (JP, A) JP-A-1-196351 (JP, A) JP-A-63-218388 (JP, A) JP-A-62-28265 (JP, A) JP-A-63-286362 (JP, A) JP-A-61-41560 (JP, A) JP-A-58-132574 (JP, U) (58) Surveyed field (Int.Cl. ⁶ , DB name) B41J 2/36 B41J 2/375 B41J 29/46 B41J 29/42

Claims (4)

(57) [Claims] 1. An image recording apparatus for recording image information on recording paper using a thermal recording head, comprising: speed detecting means for detecting a recording speed in a sub-scanning direction during image recording; Power amount determining means for determining an upper limit of the amount of power supplied to the thermal recording head according to a recording speed; power amount calculating means for calculating the amount of power supplied to the thermal recording head every time image information is recorded; Recording stop means for stopping the recording operation of the image information when the power amount calculated by the power amount calculation means exceeds the upper limit of the power amount determined by the power amount determination means. Image recording device. 2. An image recording apparatus for recording image information on recording paper using a thermal recording head, comprising: speed detecting means for detecting a recording speed in a sub-scanning direction during image recording; Power amount determining means for determining an upper limit of the amount of power to be supplied to the thermal recording head during one-line recording according to the recording speed; and determining the amount of power supplied to the thermal recording head every time one line of image information is recorded. Power amount calculation means to calculate, and a recording stop means to stop the image information recording operation when the power amount calculated by the power amount calculation means exceeds the upper limit of the power amount determined by the power amount determination means An image recording apparatus comprising: 3. An image recording apparatus for recording image information on recording paper using a thermal recording head, wherein a speed detecting means for detecting a recording speed in a sub-scanning direction during image recording, and a speed detected by the speed detecting means. Power amount determining means for determining an upper limit of the amount of power supplied to the thermal recording head according to a recording speed; power amount calculating means for calculating the amount of power supplied to the thermal recording head every time image information is recorded; A recording stop unit for stopping a recording operation of image information when the power amount calculated by the power amount calculation unit exceeds an upper limit of the power amount determined by the power amount determination unit; and a recording operation by the recording stop unit. An image recording apparatus, comprising: a recording restart unit that restarts a recording operation when the stop time exceeds a predetermined time when the recording is stopped. 4. An image recording apparatus for recording image information on recording paper using a thermal recording head, comprising: a speed detecting means for detecting a recording speed in a sub-scanning direction during image recording; Power amount determining means for determining an upper limit of the amount of power supplied to the thermal recording head according to a recording speed; power amount calculating means for calculating the amount of power supplied to the thermal recording head every time image information is recorded; When the power amount calculated by the power amount calculating means exceeds the upper limit of the power amount determined by the power amount determining means, or when the recording speed detected by the speed detecting means is lower than a predetermined value, the image is displayed. An image recording apparatus, comprising: recording stop means for stopping an information recording operation.