FR2666470A1 - Fax machine with control of printing speed - Google Patents

Abstract

The fax machine comprises a thermal printing head of line type for printing data, sent by another fax machine (7), on thermal paper scrolling on a drum (3) driven in rotation by a stator motor (4), with means (5) for controlling its speed, and a support (1, 6) of protocol software for exchanges with the other fax machine (7). It also includes a switch member (12) for controlling the speed control means (5) as well as the exchange protocol software (6). The fax machine may use standard paper and low-energy paper.

Description

The present invention relates to a facsimile machine comprising a line type thermal printing head, with a strip of heating elements and activation means, arranged to print data, transmitted by another fax machine and received in reception means, on a thermal paper scrolling on a drum helped in rotation by a stepping motor, with means for controlling its speed, and a software protocol support for exchanges with the other fax machine.

The speed of the drum drive stepper motor, and therefore the paper printing speed, depend, on the one hand, on the activation time activation of the elements of the thermal head necessary to heat them and, d On the other hand, the amount of heat necessary to make the writing pixels appear on the paper, that is to say to make the pixels of the paper turn black.

A fast head allows you to print faster than a slow head on a given paper, but at the cost of significant power and elaborate construction. A quick head is therefore expensive.

 There is so-called "low energy" paper which, conversely, on a given head, allows faster printing than standard paper. But low energy paper is more expensive than standard paper.

The printing speed of a fax machine naturally conditions the duration of exchanges between fax machines.

According to the standardized T 30 protocol, a called fax machine announces to a calling fax machine, in response to its call, by a frame called DIS (Digital Identification
Signal), its capabilities, such as the characteristics of its modem, its coding characteristics, its printing format and its printing speed. It can be 40, 20, 10, 5 or 0 ms / line. The value of 0 ms / line means that it is a memory fax machine in which the data to be printed is first received before being printed later. In the latter case, the calling fax machine can transmit its data at any speed, provided that the traffic is not too heavy and does not saturate the memory of the receiver if it cannot, due to a too low print speed, be emptied correctly on the paper. Otherwise, the calling fax machine must transmit its data at a speed respecting the printing speed of the receiving fax machine.

In local use of a fax machine, that is to say used as a photocopier, the printing speed can also be a quality criterion.

The plaintiff therefore sought to reconcile these conflicting requirements of quality and price.

To this end, the present invention relates to a facsimile machine of the type mentioned above, characterized in that it comprises means arranged to control the means for controlling the speed of the stepper motor driving the drum in rotation as well. than the exchange protocol software.

Thanks to the control means, the speed of the drum drive motor can, for example, take two values respectively associated with standard paper and with low energy paper, the thermal printing head of the facsimile machine of the invention remaining at common type. Thanks again to the control of the protocol software, the facsimile machine of the invention can, in response to a call from a facsimile machine transmitting, announce to it, in the DIS frame, one or the other of its two speeds of printing, for example 10 ms / line, for standard paper, and 5 ms / line, for low energy paper.

Advantageously, the control means comprise a tilting lever or a push button, that is to say, a switch member, accessible to an operator.

The invention is particularly remarkable in that the control means control both an electromechanical means (hardware) and a software layer (software).

In the case where the fax machine is equipped with means for controlling the contrast of the paper, for example of the type described in French patent application 89 16 181 in the name of the applicant, not yet published but which it intends to be considered as an integral part of the present application, the control means of the invention are arranged to also control these contrast control means.

The invention will be better understood on reading the following description, with reference to the single appended figure which represents a diagram of the facsimile machine.

The facsimile machine of the invention, which is organized around a microprocessor i which will be discussed below, comprises a line type thermal writing head which comprises a strip 2 of resistive elements arranged in line orthogonally in the sense of scrolling of a thermal paper scrolling on a drum 3. The drum 3 is intended to be driven in rotation by a stepping motor 4 associated with means 5 for controlling its speed.

The microprocessor 1 comprises a memory 6 supporting a software for exchange protocol with another facsimile machine 7 intended to transmit data to be printed on the paper running on the drum 3. This data is received in reception means comprising, in addition to the microprocessor 1, a switch and a modem 8. The elements of the array 2 are activated by passing a current from an activation block 9 comprising a printer card, a power source and an activation circuit controlled by microprocessor 1.

The means 5 for controlling the speed of the motor 4, themselves controlled by the microprocessor 1, comprise control electronics comprising an oscillator.

The facsimile machine, as just described, is perfectly known to those skilled in the art.

The facsimile machine shown diagrammatically in the figure furthermore comprises means 10 for controlling the contrast of the paper.

 In this case, these are those described in French patent application 89 16 181 by the applicant, to be considered here as an integral part of this description. These contrast control means 10 are inserted, like the writing head and the activation block, in a temperature control loop 11.

The contrast control means 10 make it possible, by means of the microprocessor 6 controlling the activation block 9, to vary the activation times of the elements of the strip 2.

According to the invention, the facsimile machine also includes means 12 for controlling - the electronics 5 for controlling the speed of the
motor 4 for driving the drum 3, - exchange protocol software 6, - contrast control means 10.

This is a tilting lever accessible to the fax operator. When the operator introduces plain paper into the fax machine, he switches the control 12 to the position corresponding to a printing speed here equal to 10 ms / line, which fixes the frequency of the electronics oscillator 5 at the lower of two frequencies. Thanks to the action on the software 6, the fax machine will thus control its print head at low speed and, in response to a call from the fax machine 7, will announce in the DIS frame its printing capacity of 10 ms / line. When the operator introduces low energy paper into the fax machine, he switches command 12 to the other position, corresponding to a printing speed here equal to 5 ms / line, setting the frequency of the electronics oscillator. 5 to the other, higher frequency of the two frequencies and modifying the software 6 accordingly.

Naturally, the printing speed is taken into account in the contrast control of the loop 11 by modification of the software 6 and direct control of the circuit 10.

The manual speed control could be replaced by an automatic paper type detection device. Manufacturers of thermal paper often print color bands on the back of the paper for various purposes, the device can thus consist of an optical sensor of the type described in French patent application 90 00 729 in the name of plaintiff, not yet published, but also to be considered as an integral part of this description.

The fax machine which has just been described is advantageous for a user who only needs speed in certain cases. He thus does not have to acquire an expensive fast head fax machine. It suffices to supply the fax machine of the invention with low-energy paper, allowing greater printing speed, if necessary.

Claims (4)

Claims 1. Facsimile machine comprising a line type thermal print head, with a strip (2) of heating elements and means (1, 9) for activating them, arranged to print data, emitted by a other facsimile machine (7) and received in receiving means (6, 8), on thermal paper running on a drum (3) driven in rotation by a stepping motor (4), with control means (5) of its speed, and a support (1, 6) of software for the protocol of exchanges with the other facsimile machine (7), characterized in that it comprises means (12) arranged to control the means (5) of speed control of the stepping motor (4) for rotating the drum (3) as well as the exchange protocol software (6). 2. Fax machine according to claim 1, wherein the means (12) for controlling the speed control means (5) comprises a switch member. 3. Fax machine according to claim 1, wherein the means (12) for controlling the speed control means (5) comprises an optical sensor. 4. Fax machine according to one of claims i to 3, comprising means (10) for controlling the contrast of the paper and in which said means (12) for controlling speed control means (5) control these means for controlling contrast (10).