Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
225 words
An electrostatographic single-pass multiple station printer for forming an image onto a web, which comprises: (i) a plurality of toner image-printing electrostatographic stations each having (ia) rotatable endless surface means onto which a toner image can be formed; (ib) means for line-wise forming an electrostatic toner image on each said rotatable endless surface means with a predetermined line distance; and (ic) means for transferring said electrostatic toner image onto a web; (ii) means for conveying said web along a web path in succession past said stations in synchronism with said rotatable endless surface means; and (iii) register control means for controlling operation of each of said stations in timed relationship thereby to obtain correct registering of the electrostatic toner image on said web; wherein said register control means comprises (iiia) encoder means driven by rotation of said endless surface means at one of said toner image-printing electrostatographic stations for producing pulses indicative of web displacement, and (iiib) delay means for initiating the operation of subsequent image-printing stations after a predetermined web displacement, as measured by said encoder means, has occurred, wherein said encoder means comprises an encoder sensor and electronic multiplier means for multiplying pulse frequency by a whole number factor, such that the web displacement that generates a single pulse at an output of said electronic multiplier means is smaller than the line distance.
Claim 2
Dependent Claim
225 words
An electrostatographic single-pass multiple station printer for forming an image onto a web, which comprises: (i) a plurality of toner image-printing electrostatographic stations each having (ia) rotatable endless surface means onto which a toner image can be formed; (ib) means for line-wise forming an electrostatic toner image on each said rotatable endless surface means with a predetermined line distance; and (ic) means for transferring said electrostatic toner image onto a web; (ii) means for conveying said web along a web path in succession past said stations in synchronism with said rotatable endless surface means; and (iii) register control means for controlling operation of each of said stations in timed relationship thereby to obtain correct registering of the electrostatic toner image on said web; wherein said register control means comprises (iiia) encoder means driven by rotation of said endless surface means at one of said toner image-printing electrostatographic stations for producing pulses indicative of web displacement, and (iiib) delay means for initiating the operation of subsequent image-printing stations after a predetermined web displacement, as measured by said encoder means, has occurred, wherein said encoder means comprises an encoder sensor and electronic multiplier means for multiplying pulse frequency by a whole number factor, such that the web displacement that generates a single pulse at an output of said electronic multiplier means is smaller than the line distance.
Claim 3
Dependent Claim
33 words
A printer according to claim 1, wherein said means for line-wise forming an electrostatic toner image on each said surface means are, when operative, synchronised to the pulses produced by said encoder means.
Claim 4
Dependent Claim
34 words
A printer according to claim 2, wherein frictional contact of said web with said rotatable endless surface means is capable of allowing said moving web to control rotation of said rotatable endless surface means.
Claim 5
Dependent Claim
28 words
A printer according to claim 1, wherein said factor is such that the web displacement between successive pulses is at least four times smaller than the line distance.
Claim 6
Dependent Claim
106 words
A printer according to claim 1, wherein said encoder sensor outputs an encoder signal having an encoder signal phase and said electronic multiplier means comprises a phase-locked loop circuit comprising a voltage controlled oscillator which outputs an oscillator signal having an oscillator signal frequency, divider means for dividing said oscillator signal frequency by a whole number to output a divider signal having a divider signal phase, and a phase comparator for comparing said encoder signal phase with the divider signal phase and means for controlling said voltage controlled oscillator in response to the output of said phase comparator, while said oscillator output controls said delay means.
Claim 7
Dependent Claim
46 words
A printer according to claim 1, wherein said register control means further comprises adjustment means for adjusting said delay means in response to deviations of an image register as a consequence of deviations of web displacement between two positions of image transfer, from a predetermined value.
Claim 8
Dependent Claim
24 words
A printer according to claim 1, wherein each said rotatable endless surface means is formed by an electrophotographic drum having a photoconductive peripheral surface.
Claim 9
Dependent Claim
27 words
A printer according to claim 7, wherein said drum is secured to a rotatable shaft and said encoder means comprises an encoder disc secured to said shaft.
Claim 10
Dependent Claim
20 words
A printer according to claim 7, wherein said encoder means comprises a plurality of spaced markings formed on said drum.
Claim 11
Dependent Claim
20 words
A printer according to claim 7, wherein said encoder means is associated with a central one of said image-printing stations.
Claim 12
Dependent Claim
61 words
A printer according to claim 10, which is a color printer wherein each of said image-printing electrostatographic stations are adapted for printing toner images selected from yellow, magenta, cyan and black toner images, and wherein the said image-printing station which is adapted for printing yellow toner image is located most remote from that station with which said encoder means is associated.
Claim 13
Dependent Claim
30 words
A printer according to claim 1, wherein the means for line-wise forming an electostatic toner image on said rotatable endless surface means comprises an array of image-wise modulated light-emitting diodes.
Claim 14
Dependent Claim
40 words
A printer according to claim 1, wherein said image-printing stations are arranged in first and second sub-groups, said rotatable surface means of the first sub-group forming backing roller means for the second sub-group, and vice-versa, thereby to enable duplex printing.
Claim 15
Dependent Claim
30 words
A printer according to claim 1, further comprising a cutting station for cutting the printed web into sheets, operation of said cutting station being controlled by said register control means.
Claim 16
Dependent Claim
14 words
A printer according to claim 1, wherein said web is fed from a roll.
Claim 17
Dependent Claim
60 words
A printer according to claim 1, wherein said encoder means is a rotational encoder device and said image-printing stations are substantially equally spaced as measured along said web path, such that said web advances from said transfer means of one image-producing station to said transfer means of a next image-producing station while said rotational encoder device makes one complete revolution.
Claim 18
Dependent Claim
63 words
A printer according to claim 1, wherein said encoder means is a rotational encoder device and said image-printing stations are substantially equally spaced as measured along said web path, such that said web advances from said transfer means of one image-producing station to said transfer means of a next image-producing station while said rotational encoder device makes a whole number of complete revolutions.