JPH06141161A - Facsimile equipment - Google Patents

Abstract

PURPOSE:To provide an automatic adjustment function for optimizing the density of recording images corresponding to the actual utilizing conditions of respective facsimile equipments at minimum cost. CONSTITUTION:Thermosensitive recording paper passed through an image recording position by a thermal head 3 passes through an image reading position by an image sensor 4 and is ejected. This equipment is provided with a test image memory 14 for storing image data for a recording characteristics test, a test image printing control means for reading the test image data from the memory 14 and printing them on the thermosensitive recording paper by the thermal head 3, a test image reading control means for reading the test images by the image sensor 4 when the thermosensitive recording paper printed with the test images passes through the image reading position, a test image evaluation means for processing the read data of the test images and discriminating the recording density of the test images in plural stages and a driving characteristics adjustment means for variably setting the basic value of recording power by the thermal head 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal recording type facsimile apparatus, and more particularly to an automatic adjustment technique capable of always recording an image having an appropriate density under various conditions.

[0002]

2. Description of the Related Art As is well known, in a thermal recording apparatus for a general facsimile apparatus, a drive control circuit of a thermal head drives a heating resistor in a constant voltage in a pulsed manner. The pulse width (one energization time) is set so that one black dot having an appropriate density can be recorded with sufficient driving. Further, many apparatuses are provided with an automatic adjusting means for varying the pulse width according to the temperature of the thermal head so that the recording density does not change whether the head is cold or warm.

The recording density of an image by the thermal recording apparatus varies not only with the driving characteristics (recording power) of the thermal head as described above but also with the sensitivity characteristics of the thermal recording paper used. With the widespread use of thermal recording type facsimile machines in general households, the number of manufacturers and product types of thermal recording paper has increased, and users of individual facsimile machines use different thermal recording paper from the products specified by the manufacturer. Opportunities are increasing. Each of the facsimile devices is adjusted and shipped so as to have an appropriate recording density while using a thermal recording paper specified by the manufacturer. Therefore, when non-designated thermal recording papers having different sensitivities are used, the printed image becomes too dark or too light.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 2-274167, there has been proposed a technique for automatically adjusting the driving characteristics of the thermal head according to the thermal recording paper actually set in the facsimile apparatus. In this conventional technique, when the recording paper is set in the apparatus, the test image data created in advance and stored in the memory is output and printed on the recording paper, and the above-mentioned test is performed by the density sensor provided separately. The density of the image is detected, and the driving characteristics of the thermal head are appropriately variably adjusted according to the density level.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the related art No. 4167, a dedicated sensor is provided to detect the density of the test image printed on the recording paper.
Therefore, not only is the density detection system for the test image a new cost-increasing factor, but also the sensitivity adjustment of the density detection system and the manufacturing and adjustment of the device for stabilizing the sensitivity become complicated. The price will rise considerably.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to minimize an automatic adjustment function for optimizing the density of a recorded image in accordance with the actual use situation of each facsimile apparatus. It is to realize at cost.

[0007]

Therefore, in the present invention, the density of the test image is detected by using an image sensor for reading the image of the transmission original. That is, in a facsimile apparatus having a transmission scanning unit that reads an image of an original with an image sensor and transmits the image signal, and a reception scanning unit that prints a received image signal on a thermal recording sheet with a thermal head, the image recording position of the thermal head is changed. A scanning mechanism configured such that the passed thermal recording paper is ejected after passing through the image reading position by the image sensor, a test image memory storing image data for recording characteristic test, and a test image from this memory. Test image print control means for reading data and printing on the thermal recording paper by the thermal head, and the image sensor when the thermal recording paper on which the test image is printed passes the image reading position of the scanning mechanism. A test image reading control means for reading the test image by
A test image evaluation means for processing the read data of the test image and discriminating the recording density of the test image in multiple stages;
Drive characteristic adjusting means for variably setting the basic value of the recording power by the thermal head according to the discrimination result by the evaluating means is provided.

[0008]

As a matter of course, the image sensor of the transmission scanning means has a very high performance and is highly adjusted for reading the image of the transmission original. In the scanning mechanism, the recording paper that has passed the image recording position of the thermal head then passes the image reading position of the image sensor. Therefore, the density of the test image can be accurately evaluated by printing the test image on the recording paper with the thermal head, subsequently reading the test image with the image sensor, and processing the read data of the test image. Then, when the density of the test image is too high, automatic adjustment is performed to increase the recording power of the thermal head, and in the opposite case, automatic adjustment is performed to decrease the recording power.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic structure of a scanning mechanism system in a facsimile apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 is a roll type thermal recording paper, which is pulled out from the roll by a pair of feeding rollers 7 and contacts the outer periphery of a platen 2 in the direction of arrow 5
Is transported. The thermal head 3 is arranged so as to face the outer periphery of the platen 2, and the recording paper 1 conveyed along the platen 2 contacts the thermal head 3 as described above, and an image is recorded on the recording paper 1. . Also in FIG.
Reference numeral 8 denotes a transmission document, and 6 denotes a conveyance path of the transmission document 8. As shown in the figure, the transmission original 8 passes through the outer periphery of the platen 2 in the direction opposite to that of the thermal recording paper 1. And platen 2
The image of the document 8 is read by the image sensor 4 arranged on the outer periphery of the document. What should be noted here is the positional relationship between the thermal head 3 and the image sensor 4. In the facsimile apparatus of the present invention, the thermal recording paper 1 which has passed the image recording position by the thermal head 3 is configured to be discharged by passing through the image reading position by the image sensor 4 installed immediately adjacent thereto.

Incidentally, transmission scanning means for reading the image of the transmission original 8 by the image sensor 4 and transmitting it, reception scanning means for printing the received image signal on the thermal recording paper 1 by the thermal head 3, and these means are attached. Regarding the communication control system and the image signal processing system, the facsimile apparatus of the present invention is not particularly different from the conventional general facsimile apparatus, and the description of these well-known general technical matters will be omitted.

FIG. 2 shows a schematic configuration of a portion related to the main operation of the present invention. The facsimile apparatus according to the present invention has a test image memory 14 in which image data for recording characteristic test is stored. A specific example of the test image is shown at the top of FIG. As shown in this figure, the test image is an image for two lines, black dots are dispersed evenly, and the black density of the entire test image is set to 30%.

In FIG. 2, the main control section 13 controls the overall control and data processing of the facsimile apparatus, and the control operation relating to the main part of the present invention is shown in the flowchart of FIG.

As is well known, the thermal head 3 is pulse-driven with a constant voltage, and its drive pulse width follows the value stored in the recording pulse width table 15. The table 15 is composed of a RAM and is rewritten to an appropriate value according to the test result of the recording characteristics as follows.

As shown in FIG. 3, the recording characteristic test is executed when the power of the facsimile apparatus is turned on and when a predetermined reset switch is pressed. The main controller 13 first reads the test image data from the memory 14 and supplies it to the thermal head 3 to print the test image on the thermal recording paper 1. The recording pulse width at the time of this test recording follows the value of the table 15, but the initial value of the table 15 is set at the time of factory shipment according to the characteristics of the specified recording paper.

Next, when the recording paper 1 on which the test image is printed by the thermal head 3 passes the reading position of the image sensor 4, the test image on the recording paper is read. As shown in FIG. 2, the read output of the image sensor 4 is converted into monochrome image data by the A / D converter 9 and temporarily stored in the register 10. The register 10 has a capacity for storing image data for two lines, and the read data of the test image on the recording paper is stored in the register 10 under the timing control of the main controller 13.

The read data of the test image stored in the register 10 is output in parallel to the averaging circuit 11, and the average black density of the read test image is measured. The measured black density is graded by the comparison unit 12 into four grades. In this example, if the black density is 28% or more, it is regarded as normal, and the same value 1 msec as that at the time of factory shipment is stored in the table 15. When the recording density is smaller than this, a larger value of 2 msec, 3 msec or 4 msec is stored (rewritten) in the recording pulse width table 15 according to the grade. In this way, by rewriting the values in the table 15 according to the test result of the recording characteristics, it becomes possible to record the test image at a density close to the set 30%.

[0017]

As described above in detail, according to the present invention, the density of the test image printed on the recording paper is detected by using the image sensor for reading the image of the transmission original, so that the test image as in the prior art is used. A dedicated sensor system for the density detection is unnecessary, and the function of automatically adjusting the recording characteristics based on the print result of the test image can be realized at low cost. In particular, since the image sensor of the transmission scanning means is a highly accurate and high performance one, it is possible to perform the automatic adjustment of the thermal recording device with high accuracy by using this, and to use a dedicated density detection system. There is no need to adjust the sensitivity of.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a scanning mechanism system in a facsimile apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration block diagram of an automatic adjustment system of a heat-sensitive recording unit in the apparatus of the above embodiment.

FIG. 3 is a flowchart of a control procedure of an automatic adjustment operation in the apparatus of the above embodiment.

FIG. 4 is an operation explanatory view of an automatic adjustment operation in the above-mentioned embodiment apparatus.

[Explanation of symbols]

 1 Thermal recording paper 2 Platen 3 Thermal head 4 Image sensor 8 Transmission document

Claims (1)

[Claims] 1. A facsimile apparatus comprising: a transmission scanning means for reading an image of an original by an image sensor and transmitting it; and a reception scanning means for printing a received image signal on a thermal recording paper by a thermal head. A scanning mechanism configured such that the thermal recording paper that has passed the recording position passes through the image reading position by the image sensor and is discharged, a test image memory that stores image data for a recording characteristic test, and this memory. Test image print control means for reading test image data from the thermal head and printing it on the thermal recording paper by the thermal head, and when the thermal recording paper on which the test image is printed passes the image reading position of the scanning mechanism. Test image reading control means for reading the test image by the image sensor, Test image evaluation means for processing read data of the test image to discriminate the recording density of the test image in multiple stages, and drive characteristics for variably setting the basic value of the recording power by the thermal head according to the discrimination result by the evaluation means. A facsimile machine comprising an adjusting means.