US3851236A

US3851236A - Apparatus for automatically controlling the speed of travel of an original and of copying material in a copying machine

Info

Publication number: US3851236A
Application number: US00336361A
Authority: US
Inventors: W Dennhardt; H Schroter
Original assignee: Kalle GmbH and Co KG
Current assignee: Kalle GmbH and Co KG
Priority date: 1972-03-01
Filing date: 1973-02-27
Publication date: 1974-11-26
Anticipated expiration: 1991-11-26
Also published as: ES412126A1; BE795971A; NL7302278A; ATA170073A; AT344004B; DE2209725A1; SE377197B; GB1417334A; FR2174629A5; IT977523B; DE2209725C2; CA981085A

Abstract

Apparatus is disclosed for automatically controlling the speed of travel of an original and of copying material in dependence upon the transparency of the original and upon the photosensitivity of the copying material, for use in a copying machine that contains at least two kinds of copying materials selectible by the original and which includes at least one photosensitive device for measuring the transparency of the original and a driving motor the speed of which can be controlled by the output signal from the photosensitive measuring unit. The apparatus comprises at least two amplifier means which may be connected selectively into a control circuit for the driving motor, a preselector switch means associated with each kind of copying material, which switch means may be connected into the control circuit and by means of which an amplifier means for the kind of copying material may be preselected, and a sensing means in the path of travel of the original associated with each kind of copying material which is effective, upon actuation by the original, to switch the preselector switch means associated with the selected kind of copying material, and the amplifier means preselected by the switch, into the control circuit.

Description

United States Patent [191 Dennhardt et al.

[ Nov. 26, 1974 APPARATUS FOR AUTOMATICALLY CONTROLLING THE SPEED OF TRAVEL OF AN ORIGINAL AND OF COPYING MATERIAL IN A COPYING MACHINE [75] Inventors: Werner Dennhardt; Herbert Schroter, Hahn/Taunus, both of Germany [73] Assignee: Kalle Aktiengesellschaft,

Weisbaden-Biebrich, Germany 22 Filed: Feb. 27, 1973 21 Appl. No.: 336,361

[30] Foreign Application Priority Data Mar. 1, 1972 Germany 2209725 [52] 11.5. CI 318/313, 318/467, 318/480, 355/14 [51] Int. Cl. H02p 5/16, G03g 15/00 [58] Field of Search 355/14; 318/313, 466, 467, 318/480 [56] References Cited UNITED STATES PATENTS 3.684.940 8/1972 Lutz 318/345 3,700,323 10/1972 Guyette 355/14 FOREIGN PATENTS OR APPLICATIONS 1.522.790 12/1965 Germany 2,119,373 4/1971 Germany Primary ExaminerRobert K. Schaefer Assistant Examiner-Thomas Langer Attorney, Agent, or Firm-James E. Bryan [5 7] ABSTRACT Apparatus is disclosed for automatically controlling the speed of travel of an original and of copying material in dependence upon the transparency of the original and upon the photosensitivity of the copying material, for use in a copying machine that contains at least two kinds of copying materials selectible by the original and which includes at least one photosensitive device for measuring the transparency of the original and a driving motor the speed of which can be controlled by the output signal from the photosensitive measuring unit. The apparatus comprises at least two amplifier means which may be connected selectively into a control circuit for the driving motor, a preselector switch means associated with each kind of copying material, which switch means may be connected into the control circuit and by means of which an amplifier means for the kind of copying material may be preselected, and a sensing means in the path of travel of the original associated with each kind of copying material which is effective, upon actuation by the original. to switch the preselector switch means associated with the selected kind of copying material, and the amplifier means preselected by the switch, into the control circuit.

12 Claims, 5 Drawing Figures PATENTEL HOW/26 I974 SHEET 10F 5 Fig.1

PATENTE i :i'uvzelsm SHEET 2 [IF 5 APPARATUS FOR AUTOMATICALLY CONTROLLING THE SPEED OF TRAVEL OF AN ORIGINAL AND OF COPYING MATERIAL IN A COPYING MACHINE The present invention relates to apparatus for automatically controlling the speed of travel of an original and of copying material, for use in a copying machine which may be loaded with more than one kind of copying material that may be selected to suit the original. The copying material may be provided in the form of sheets or in the form of endless webs on a plurality of supply rolls.

ln copying machines where light from a source is passed through the original to be copied, the exposure time required, i.e., the rate of travel of the original and of the copying material required, depends upon the transparency of the original. It has previously been proposed to measure the transparency of the original by means of a photosensitive measuring unit, of which the output signals control the speed of the driving motor for transporting the original and copying material.

Types of copying material having differing degrees of photosensitivity are used in copying machines. It is therefore not sufficient to control the speed of travel merely in dependence upon the transparency of the original. In order to obtain copies having a good background, the photosensitivity of the copying material used also has to be taken into account. German Auslegeschrift No. 1,522,790 discloses an apparatus for automatically controlling the speed of travel of an original and of copying material, in which the transparency of the original is measured with the aid of a CdS photoresistor, the resistance of which determines the potential of a condenser which stores the potential, so that the constant speed of travel that has been determined is maintained during the copying of an original. When copying material having a different photosensitivity is also being treated in this apparatus, a resistor may be switched in or bridged in order to suit the copying speed to the photosensitivity of two kinds of copying material.

ln the apparatus for controlling the speed of travel of an original and of copying material, described in German Offenlegungschrift No. 2,1 19,373, an amplifier is moved into the amplifying and zero crossover conditions with the aid of potentiometers in order to match the particular photosensitivity of the copying material that is being used.

The present invention provides apparatus for automatically controlling the speed of travel of an original and of copying material in dependence upon the transparency of the original and upon the photosensitivity of the copying material, for use in a copying machine that contains at least two kinds of copying materials selectible by the original and which includes at least one photosensitive device for measuring the transparency of sociated with each kind of copying material which is effective, upon actuation by the original, to switch the preselector switch associated with the selected kind of copying material, and the amplifier unit preselected by the switch, into the control circuit.

In the apparatus of the invention, the exposure time, i.e'., the speed of travel of the original and of the copying material, is automatically controlled both in dependence on the transparency of the original and on the photosensitivity of the kinds of copying material selected to suit the original.

The photosensitive device for measuring the transparency of the original preferably comprises a plurality of photosensitive elements that are as small as possible in order to increase the likelihood of effecting measurement of the photosensitivity of any area of the original that carries no written matter. For the same reason it is advantageous so to arrange the photosensitive elements that they are offset from each other in the direction parallel with and/or at right angles to the direction of travel of the original. If the photosensitive measuring unit consists of a plurality of photosensitive elements, then a discriminator should be connected downstream of the measuring unit to select from the signals measured at the photosensitive elements that corresponds to the greatest light intensity received, indicating the greatest degree of transparency.

Photoresistors, photoelectric cells and the like can be used in the customary manner as the photosensitive elements.

If the originals are always to be introduced on the same guide bar of the feed table, then one photosensitive measuring unit is sufficient. If on the other hand the originals, depending upon their width, are to be introduced on the right-hand or left-hand guide bar of the feed table, at least two photosensitive measuring units should be provided.

The apparatus of the invention includes at least two amplifiers which, with the aid of a preselector switch, can be preselected to suit the kind of copying material with which the switch is associated. With two amplifiers it is possible to process two kinds of copying material that differ as regards their photosensitivity. A further amplifier unit is necessary for each additional kind of copying material having a different degree of photosensitivity. The amplifier units may be amplifiers having differing gain; alternatively, the units may all contain one and the same amplifier and may differ as regards the resistors connected to this amplifier; for example the amplifier unit 1 may consist of an amplifier V1, the amplifier unit 2 the amplifier V1 with connected resistors R1 and R2, and the amplifier unit 3 the amplifier Vl with connected resistors R3 and R4, and so on.

The apparatus of the invention is for use with a copying machine having a supply of at least two kinds of copying material, which may be selected to suit the original. The apparatus of the invention is equally suitthe original and a driving motor the speed of which can able for machines in which the copying material may be provided in the form of sheets and for machines in which the material may be provided in the form of endless webs on a plurality of supply rolls from which it may be automatically drawn and severed. A selector switch is provided for each kind of copying material and is used for preselecting the amplifier unit for the kind of material associated with the switch, the amplifier unit corresponding to the photosensitivity of the copying material. For example, if the copying machine is to be provided with a supply of four kinds of copying material, then four preselector switches are present. The various kinds of copying material may either take the form of sheets arranged in several stacks or of rolls of material which is drawn off from the rolls and cut to length in accordance with the length of original that has been determined by a probing operation. The types of copying material may differ in various ways, e.g. as regards width and photosensitivity, and in the case of stacks of sheet material, as regards length.

In the apparatus of the invention, a sensing device is provided in the path of travel of the original. For example, a device for selecting copying material depending on the width of the original suitably may consist of one or more switching elements associated with each kind of copying material. The switching elements may be mechanical switches, for example, micro-switches, photoelectric switches, for example photoelectric cells, or inductive proximity switches. If the originals are always to be introduced on the same side of the feed table, then one switching element in the path of travel of the original suffices for each type of copying material loaded in the machine. The switching elements for the various types of copying material may be so arranged in the path of travel of the original that the leading edge of the original reaches them one after the other. If, depending upon their width, the originals are introduced on the left-hand or the right-hand side of the feed table and if, according to their width, for example, three different kinds of copying material can be selected by the original, then according to the invention use is made of a special grouping of switches to be described in greater detail below.

In a copying machine in which the wider originals also actuate the sensing devices for the narrower originals on their way to the exposure unit or vice versa, a control unit may be associated with each kind of copying material and therefore with each sensing device. When an original reaches a sensing device this results in actuation of the control unit associated therewith which both connects the preselector switch, associated with the selected type of copying material, into the control circuit and blocks the control units associated with the other kinds of copying material. This prevents other preselector switches from being connected into the control-signal circuit when the same original then actuates the sensing device to select another kind of copying material. The blocking signal of the control unit keeps the correct preselector switch and therefore the correct amplifier unit connected into the control circuit while an original is passing through the exposure unit.

The sensing devices, if situated at an appropriate point along the path of travel of the original, can at the same time also take over the function of controlling the mechanisms for paying out the rolls of copying material and that of controlling the cutting means. However these functions are preferably perfonned by another group of switches.

nal reaches the copying unit, and the retrieved signal being erased.

When an original is introduced into the copying machine, it first travels at the speed determined by the transparency of the last original until the output signal associated with the fresh original is retrieved from the storage unit and the speed of the driving motor adjusted accordingly. This is disadvantageous when the transparency of the preceding unit is low and the speed of travel correspondingly low. It is therefore advantageous to provide a delay unit which is controllable by the sensing means and which switches the driving motor to a pre-set idling speed when an original leaves the exposure unit.

Instead of a delay unit controllable by the sensing means, it is also possible to fit behind the copying cylinder, a further sensing means which when actuated by the emerging original switches the driving motor to a pre-set idling speed.

If an original having a very low transparency is introduced into the copying machine, and if a very low speed of travel is accordingly required, then, depending upon the characteristics of the regulator controlling the driving motor, the motor may stop. To prevent this a voltage which corresponds to the lowest running speed of the driving motor may be continuously applied to the regulator. If an original of very low transparency is then introduced into the copying machine and, based on this measured transparency, there is applied to the regulator a voltage that is lower than the minimum voltage continuously received by the regulator, the driving motor continues to run at a speed that corresponds to this minimum voltage. Time-consuming stoppages are thus avoided. In this arrangement it is of course also possible for the driving motor to be switched to a preset idling speed.

The light from the source employed for copying is preferably used for measuring transparency, so that any fluctuations in the emission of light from the source used for copying can be taken into account. The light from the source used for copying may be transmitted to the photosensitive measuring unit by means of mirrors, metal tubes or preferably photoconducting filaments that are capable of transmitting ultra-violet light.

According to the invention, the differing photosensitivities of copying materials used in copying machines are catered for by the amplifier units which are selectively connectible into the control circuit. It is found in practice that copying materials that should possess the same degree of photosensitivity actually exhibit differing photosensitivities resulting, for example, from their being stored for different periods of time. These deviations from the theoretical value are not so great that a photosensitivity is reached for which another amplifier unit would be appropriate. Fine adjustment is therefore required in the amplifier unit, pre-selected for the photosensitivity of a given type of copying material, if the actual photosensitivity deviates from the theoretical value, in order to obtain copies having the correct background. This may be achieved by altering the amplification characteristics (gain) of the amplifier unit by displacing at least two potentiometers. This solution, however, is not satisfactory if the copying machine is supplied with copying materials on two selectible rolls and the materials differ only as regards length, are intended to be of the same photosensitivity but in fact vary in this characteristic, as a result of one roll having been in stock for a longer period than the other. The same amplifier unit would be selected for both rolls with the aid of the preselector switches associated with them. This intensifier unit pre-selected for both rolls however can be set to only one of the two photosensitivities by means of the potentiometers. If the roll hav ing the other photosensitivity is selected, copies having a less satisfactory background are obtained since the amplifier unit is set to suit another photosensitivity.

This problem may be solved with the aid of control I means designed along the following lines. -At least two amplifier units, selectively connectible into the controlsignal circuit, may be provided for each type of copying material used in the machine. If, for example, the machine is using two rolls of copying materials which are intended to have the same photosensitivity but which however differ from each other in this respect, then a separate amplifier unit can be pre-selected for each roll; the two amplifier units initially may be the same as regards their intensification characteristics, but can then be finely adjusted to various extents by setting at least two potentiometers for each intensifier unit.

Alternatively, there may be, associated with each kind of copying material, an amplifier which may be connected in series with the amplifier unit pre-selected for the kind of copying material when the sensing dethrough the filters 9a to 9e, and 9a to 9'e respectively and on to the photosensitive elements 8a to 8e, and 8'a to 8'e, respectively, which measure the transparency of the original 1, 2 or 3 (see FIG. 3). By way of the amplifier 10a to 10e, and l0'a to l0e, the output signals, from the photosensitive elements 8a to 8e, and 8'a to 8'e and based on the measured transparency, pass through the discriminators 11 and 11' respectively. The discriminators l] and 11 select the signal that corresponds to the greatest transparency.

If the original 1 having a width a1 is fed into the copying machine, its transparency is measured by the photosensitive measuring unit 8, since the switch S1, which establishes contact between the photosensitive measuring units 8 and 8' and the remaining part of the measuring system, normally bears against the contact 13 (see FIGS. 2 and 3). If on the other hand the original 2 having a width a2 is introduced into the copying machine, then during its travel it actuates the switch S2 which, as long as it is contacted by the original 2, applies the switch S1 to the contact 12' by way of a reversing switch unit 13, so that the photosensitive measuring unit 8' measures the transparency. The same thing occurs when the original 3 having a width a3 is introduced into the machine. If an original 3' having a width a'3 is 7 fed into the machine, then it operates the switch S2 vice is actuated by an original. This embodiment is described in more detail below.

Two embodiments of the invention will now be described in greater detail, by way of example only, by reference to the accompanying drawings.

In these embodiments the apparatus of the invention includes control means which enables output signals from a number of originals to be stored and, shortly before an original enters the exposure unit, permits the output signal associated with this original to be retrieved. In the drawings:

FIG. 1 shows a diagrammatic plan view of the path of travel of the originals downstream of the exposure unit (the size of the originals and the distances between the probe switches are not drawn to scale);

FIG. 2 is a detailed circuit diagram of the control apparatus between the photosensitive measuring units and the amplifier units;

FIG. 3 shows a block circuit diagram of the entire control apparatus;

FIG. 4 is a detailed circuit diagram for the amplifier means for the first embodiment, and

FIG. 5 is a detailed circuit diagram for the amplifier means for the second embodiment.

Depending upon whether an original 1 of the width a1, and original 2 of the width a2, or an original 3 of the width a3 is fed into the copying machine, one of the webs of copying material carried on the supply rolls 4, 5 and 6 is selected (see FIG. 1). An original 1 having a width a1 is introduced along the left-hand guide bar (not shown) of the feed table, an original 2 having a width a2 is introduced along the right-hand guide bar, and an original 3 having a width a3 is introduced on either the left or the right.

On its way to the exposure unit 7, one of the

originals

1, 2 or 3 passes at least one of the photosensitive devices 8 and 8' each of which consists of the photosensitive elements 8a to 8e and 8'a to 8'e respectively. At this point an original 1, 2 or 3 is irradiated with light from the source used for copying, which light passes only if it is introduced on the right-hand side of the feed table. Only then is its transparency measured by the photosensitive measuring unit8';

In the path of travel of the

originals

1, 2 and 3, the two switching elements S11 and S12 are positioned upstream of the photosensitive measuring units 8 and 8'. The two switching elements S3 and S4 for storage purposes are positioned downstream of the measuring units. The switching elements S3 and S11 are connected by the AND gate 23, and the switching elements S4 and 812 by the AND gate 24 (see FIG. 2). Each AND

gate

23 and 24 passes a signal at its output only when a signal is passed simultaneously to its two inputs. Thus a signal is passed on only when the switching elements S3 and S1 1 or S4 and S12 are simultaneously actuated by the original. Connected downstream of the two AND

gates

23 and 24 is an OR gate 25. This OR gate passes a signal to the switch S5 as soon as a signal comes from one of the two AND

gates

23 or 24. The switch S5 is then closed for this period. The arrangement whereby the switching elements 53, S4, S11, and S12 are operated by way of the AND

gate

23 and 24 and the OR gate 25 is referred to as a measuring time switch in the block circuit diagram of FIG. 3 and is designated therein by the numeral 26.

At least one of the switching elements S11 and S12 and at least one of the switching elements S3 and S4 is actuated by an original 1, 2 or 3 introduced into the copying machine. As soon as the leading edge of an original reaches one of the switching elements S3 or S4, a brief electrical impulse is released by way of the electronic switch 140, which impulse causes the sliding contact 16a in the first stepping switch unit 15a (for the storage unit) to move through one switching interval to the next pair of contacts a, b, c or d. At the same time and as long as one of the switching elements S11 or S12 is covered by an original 1, 2 or 3, the switch S5 is closed and the

photosensitive measuring unit

8 or 8 is connected to the storage unit 18 through the stepping switch unit 15a.

Positioned downstream of the switching elements S3 and S4 in the path of movement of the originals are sensing devices which consist of the switching elements S6, S7, S8 and S9. As soon as one of the switching elements S6 or S7 is reached by the leading edge of an original, a brief electric impulse is released through the electronic switch 14b, which impulse causes the sliding

contacts

16b and 16b in the second stepping switch unit 15b to move to the next contact a, b, c or d, and a", b, c", or d" respectively (see FIG. 2). The output signal produced by means of an original 1, 2 or 3 is retrieved from the storage unit 18, and at the same time the output signal caused by the preceding original is erased in the storage unit 18 by way of the resistor 22.

As can be seen from FIGS. 3 and 4, the switching elements S6, S7, S8 and S9 are connected to the OR gate 27 which, as soon as one of the switching elements is actuated by the leading edge of an original, sends an impulse to the delay unit 28. This causes the switch S16 to be applied immediately to the contact 29. As soon as the trailing edge of an original uncovers the switching elements, the delay unit 28 interpolates a delay period, upon the expiration of which the switch S16 is lifted from the contact 29 and is applied to the contact 29', so that the regulator 20 is connected to the power supply element 30. The voltage now applied to the regulator 20 can be pre-set and is preferably so selected that the driving motor 21 runs at its highest possible speed.

As can be seen from FIGS. 3 and 4, a voltage is applied to the regulator 20 through a minimum value setting device 31, when the switching element S16 is applied to the contact 29. The minimum value setting device 31 used may be, for example, a potentiometer combined with diodes, by means of which potentiometer there is applied to the regulator 20 the voltage corresponding to the lowest running speed of the driving motor 21.

The sensing device consisting of the switching elements S6, S7, S8 and S9 at the same time also taken over the function of connecting that

amplifier

19a, 19b, 19c or 19d that corresponds to the photosensitivity of the selected

roll

4, or 6 of copying material into the control signal circuit. The switching element S6, the control unit 36, the switch S13 and the pre-selector switch 39 are associated with the roll 4 of copying material, the switching element S7, the control unit 38, the switch S and the. pre-selector switch 41 with the roll 5 of copying material, and the switching elements S8 and S9, the control unit 37, the switch S14 and the preselector switch 40 with the roll 6 of copying material. If for example a fresh roll 4 is placed in the copying machine, then depending upon the photosensitivity of the fresh roll, an

amplifier

19a, 19b, 19c or 19d is preselected by means of the pre-selector switch 39. If the roll 4 is later selected by an original, the pre-selected amplifier is switched into the control circuit. The same applies as regards the

rolls

5 and 6 and the pre-selector switches 40 and 41. If it is required to copy on more than four copying materials having differing photosensitivities, then a correspondingly greater number of pre-selectible amplifiers must be provided.

A sensing device consisting of two switching elements is provided for the roll 6. One of these switching elements is positioned forwardly of the switching elements S6 and S7 for the

rolls

4 and 5 along the path of travel of the originals, and the other is positioned rearwardly thereof. The two switching elements are connected in paralel. When one of the two switching elements is actuated by the original, a blocking signal is sent through the control unit 37 to the

other switching elements

36 and 38, i.e., the switches S13 and S15 remain open although the switching elements S6 and S7 are actuated by the original 3.

The mode of operation of the apparatus will now be described. The roll 4 comprises a copying material having a photosensitivity which corresponds to the amplifier 19a so that the latter is pre-selected by the preselector switch 39. The photosensitivity of the copying material of the roll 6 corresponds to the amplifier 1912 so that the pre-selector switch 40 will have been applied to the contact associated with the amplifier 19b, when the roll 6 was placed in the copying machine. The amplifier 190 is pre-selected for the roll 5.

If for example the original 1 is introduced into the copying machine it first reaches the switching element S11 and then passes over the photosensitive measuring unit 8. As soon as the leading edge of the original reaches the switching element S3, the latter is applied to the contact 32. This causes an impulse to be passed to the electronic switch 14a so that the sliding contact 16a is moved from the pair of contacts a to the pair of contacts b. At the same time the switch S5 is closed when the switching elements S3 and S1 1 are both actuated by the original 1. This causes the photosensitive measuring unit 8 to be connected to the condenser C2 of the storage unit 18 by way of the stepping switch unit 15a. The condenser C2 is charged to a level corresponding to the transparency of the original 1 measured in the photosensitive measuring unit 8. As soon as the trailing edge of the original has uncovered the switching element S11, the switch S5 is opened again.

The original 3 may be introduced into the machine immediately after the original 1. The original 3 actuates the switching elements S11 and S12, passes over the

photosensitive measuring units

8 and 8 and closes the switching element S2. The switch S1 is lifted from the contact 12 with the aid of the reversing switch unit 13 and is applied to the contact 12'. As soon as the original 3 reaches the switching elements S3 and S4, the sliding contact 16a is moved to the pair of contacts c and the switch S5 is closed. The photosensitive measuring unit 8' is thus connected to the condenser C3 which is charged to a level corresponding to the transparency of the original 3.

In the meantime the original 1 has reached the switching element S6 which is lifted from the contact 34' and is applied to the contact 34', this causes a brief inpulse to be released at the electronic switch 14b, which impulse moves the sliding

contacts

16b and 16b in the stepping switch unit 15b to the contacts b and b" respectively. The reversal of S6 so that it is applied to the contact 34 at the same time causes the delay unit 28 to be operated by way of the OR gate 27 and this unit immediately applies the switch S16 to the contact 29 (see FIGS. 3 and 4). Also, the reversal of S6 actuates the control unit 36 which delivers blocking signals to the

control units

37 and 38, so that the switches S14 and S15, if they have been closed, are opened, and at the same time S13 is closed. The signal caused to be produced by the original 1 and stored in the condenser C2 is applied by way of the amplifier 19a to the regulator 20 which regulates the speed of the driving motor 21. If the value of the voltage passing from the amplifier 19a is less than the voltage applied to the regulator 20 through the minimum value setting device 31, then the driving motor 21 continues to run at a speed that corresponds to the voltage deriving from the minimum value setting device 31. If the value of the voltage deriving from the amplifier 19a is greater than that from the minimum value setting device 31, the driving motor 21 runs at a speed which corresponds to the voltage passing from the intensifier 19a. The original 1 travels through the exposure unit 7 at a speed that corresponds to its transparency and to the photosensitivity of the roll 1 that it has selected.

The shifting of the sliding contact 16b will have caused the condenser C1 to discharge through the resistor 22. When the trailing edge of the original 1 leaves the switching element S6, the latter is again applied to the contact 34', so that the delay element 28 interpolates a given delay period upon the expiration of which the switch S16 is applied to the contact 29. The voltage from the supply element 30 is thus supplied to the regulator 20. The length of the delay period is such that upon expiration of this period the original 1 will have left the exposure unit 7. In the arrangement illustrated in FIG. 4, the switch S13 remains closed until a fresh original has actuated the sensing device S7 or 88/89. The switch S13 can however also be opened again by the delay unit 28 upon expiration of the delay period.

On its way to the exposure unit 7 and after it has reached the switching elements S3 and S4, the forward edge of the original 3 first actuates the switching element S8. This causes the control element 37 to be actuated and thus a blocking signal to be passed to the

control units

36 and 38 so that the switches S13 and S15, if they have been closed, are opened, and the switch S14 is closed. At the same time the switch S16 is applied immediately to the contact 29 by way of the OR gate 27 and the delay unit 28. Thus, the signal from the condenser C2, which has stored the signal produced by the original 1, is first applied to the amplifier 19b. As soon as the leading edge of the original 3 has reached the switching element S6 and/or S7, the latter are applied to the

contacts

34 and 35 respectively. The electronic switch 14b thus receives the signal so that the sliding

contacts

16b and 16b move to the contacts c and Thus the signal is now retrieved from the condenser C3 which has stored the signal caused by the original 3. The original 3 moves into the exposure unit 7 at a speed that corresponds to its transparency and to the photosensitivity of the roll 6 of copying material that it has selected. The shifting of the sliding contact 1612 causes the condenser C2, in which the signal caused by the original 1 has been stored, to discharge through the resistor 22. When the trailing edge of the original 3 uncovers the switching element S8, the

control units

36 and 38 continue to be blocked since the switching element S9 is still actuated by them. This latter switching element is the last one to be uncovered by Y the original 3. Only when the trailing edge of the original has uncovered the switching element S9 are the

control elements

36 and 38 freed and is the switch S16 again applied to the contact 29 after a certain delay period.

The use of two switching elements for the device for probing the roll 6, and the arrangement of these two switching elements S8 and S9 opposite the switching elements S6 and S7 ensures that first the control element 37 is actuated and thusthe correct switch S14 closed and that, although the switching elements S6 and S7 for the

rolls

4 and 5 are also actuated by the original 3, the

control units

36 and 38 remain blocked as long as the switching elements S6 and S7 are actuated by the original 3. As long as the original 3 is passing through the exposure unit 7 the correct amplifier 19b in the present case, is connected into the control signal circuit through the switch S14.

FIG. 5 shows an arrangement with which it is possible to use rolls of

material

1, 2 and 3 which, although intended to be of similar photosensitivity in fact vary in this characteristic from roll to roll within certain limits. The same amplifier, e.g., 19a, is pre-selected, according to the theoretical level of the photosensitivity of the copying materials, by means of the pre-selector switches 39, 40 and 41 for the

rolls

1, 2 and 3. Apart from the four amplifiers 19a to 19d (these have differ ent characteristics in FIG. 5 from those illustrated in FIG. 4), three further amplifiers 42a, 42b, and 420 are provided, each associated with a roll of copying material. The amplifiers 42a, 42b and 420 can be selectively connected into the control circuit, i.e. that amplifier with which the selected type of copying material is as sociated is switched in. The amplification (gain) of each of the amplifiers 42a, 42b and 420 can be adjusted individually; thus any deviation in photosensitivity from the theoretical level can be taken into account for each roll of copying material. When the original 1 reaches the switching element S6, the switches S13 and S13 are closed by way of the control unit 36. Thus both the amplifier 19a and the amplifier 42a are connected into the control circuit. The arrangement, just described, for effecting fine adjustment of the amplifiers 42a to 42c, which are each associated with a roll and are switched into the control circuit as second amplifiers, has the advantage over the earlier described possible arrangement, in which at least two, i.e., in the present embodiment, four amplifiers have to be provided for each roll, that a percentage variation in the speed of travel through the machine can be achieved simply by adjusting a potentiometer. In the case of the fine adjustment, the amplification characteristics of the intensifiers to 19d remain unchanged, whereas when a potentiometer is used in each case, the amplification (the rise in the amplification characteristics) of the amplifiers 42a to 42c can be adjusted while the zero crossover of the amplification characteristics of the amplifiers 42a to 42 remains unchanged. The percentage change in the speed of travel through the machine is achieved by associating the zero speed of the driving motor 21 with an input voltage at the amplifiers 42a to 42c that is likewise zero.

It will be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

What is claimed is:

1. Apparatus for automatically controlling the speed of travel of an original and of copying material in dependence upon the transparency of the original and upon the photosensitivity of the copying material, for use in a copying machine that contains at least two kinds of copying materials selectible by the original and which includes at least one photosensitive measuring unit for measuring the transparency of the original and a driving motor the speed of which is controlled by the output signal from said photosensitive measuring unit, which apparatus comprises at least two amplifier means,

a preselector switch means associated with each kind of copying material whereby one of said amplifier means is preselected for the kind of copying material which is associated with said switch,

and a sensing means in the path of travel of the original associated with each kind of copying material which is effective, upon actuation by the original, to switch the preselector switch means associated with the selected kind of copying material, and the amplifier means preselected by the switch, into the control circuit.

2. Apparatus as claimed in claim 1 including a control unit associated with each kind of copying material by means of which control unit the sensing means may be actuated by the original, which control unit simultaneously may block the control units associated with the other kinds of copying material.

3. Apparatus as claimed in claim 1 wherein the amplifier means comprise amplifiers having different amplification characteristics.

4. Apparatus as claimed in claim 1 wherein the amplifier means all contain the same amplifier to which are connected resistors that are different for each amplifier means.

5. Apparatus as claimed in claim 1 including a regulator means whereby the driving motor may be controlled, a voltage corresponding to a suitable minimum speed being continuously applied to said regulator means while the apparatus is in operation.

6. Apparatus as claimed in claim 1 which also includes a delay unit controllable by the sensing means to switch the driving motor to a suitable idling speed when an original leaves the exposure unit.

7. Apparatus as claimed in claim 1 wherein there are disposed in the path of travel of the original and downstream of the exposure unit:

1. at least one switching element means for the storage operation, which switching element means, upon being actuated by the leading edge of an original a. operates a first stepping switch unit and b. through this stepping switch unit connects the photosensitive measuring unit to a storage unit for a certain period, and 2. at least one switching element means for retrieval and erasure purposes, which switching element means, upon being actuated by the leading edge of an original, operates a second stepping switch unit, so that a. the stored signal caused by the original is passed by way of an amplifier means to a regulator for regulating the speed of the driving motor, and

b. the stored signal caused by the preceding original is erased.

8. Apparatus as claimed in claim 1 wherein at least two amplifier means are provided for each kind of copying material.

9. Apparatus as claimed in claim I wherein there is associated with each kind of copying material an amplifier which may be connected in series with the amplifier means preselected for the kind of copying material, when the sensing means is actuated by an original.

10. Apparatus as claimed in claim 1 wherein the photosensitive device comprises a plurality of photosensitive elements, arranged so as to be offset from each other.

11. Apparatus as claimed in claim 10 wherein a discriminator is connected downstream from the photosensitive device to select from the measured output signal the output signal corresponding to the greatest transparency.

12. Apparatus as claimed in claim 1 wherein the sensing means comprises at least one switching element associated with each kind of copying material arranged in the path of travel of the original to sense the width of the original.

Claims

1. Apparatus for automatically controlling the speed of travel of an original and of copying material in dependence upon the transparency of the original and upon the photosensitivity of the copying material, for use in a copying machine that contains at least two kinds of copying materials selectible by the original and which includes at least one photosensitive measuring unit for measuring the transparency of the original and a driving motor the speed of which is controlled by the output signal from said photosensitive measuring unit, which apparatus comprises at least two amplifier means, a preselector switch means associated with each kind of copying material whereby one of said amplifier means is preselected for the kind of copying material which is associated with said switch, and a sensing means in the path of travel of the original associated with each kind of copying material which is effective, upon actuation by the original, to switch the preselector switch means associated with the selected kind of copying material, and the amplifier means preselected by the switch, into the control circuit.

2. at least one switching element means for retrieval and erasure purposes, which switching element means, upon being actuated by the leading edge of an original, operates a second stepping switch unit, so that a. the stored signal caused by the original is passed by way of an amplifier means to a regulator for regulating the speed of the driving motor, and b. the stored signal caused by the preceding original is erased.

9. Apparatus as claimed in claim 1 wherein there is associated with each kind of copying material an amplifier which may be connected in series with the amplifier means preselected for the kind of copying material, when the sensing means is actuated by an original.