Abstract: A highly accurate and stable, but continuous fixed-phase fixed-frequency, quartz crystal oscillator frequency source, typically of 80 Mhz frequency, is used as the primary frequency standard for (i) synchronized, and (ii) variable, pixel placement timing in a bee-scanning image generator. A fixed-frequency timing chain appropriately synchronized to the scanning energy beam is generated by selecting, in accordance with a sensed start-of-scan condition, from among a number, typically 23, of variably-phase-delayed, typically by less than 1 nanosecond and normally by 0.8 nanosecond, replications of a fixed-phase timing chain that is produced from the crystal oscillator. The synchronized fixed-frequency timing chain so derived is then converted to the required variable-frequency pixel placement timing chain by timing-data-driven recombination of variably-phase-delayed replications, typically 13 such replications at a delay of 1.

Abstract: In a high-speed image scanner, a driving method is proposed which needs no timing adjustment between the sensor driving pulse and the motor drive pulse required when the motor shifts from an accelerated state to a constant-speed state. The period of the sensor driving pulse is selected to be equal to or 1/N (N=integer) of that of the motor drive pulse at the time of constant-speed operation, and the phases of the sensor driving pulse and motor drive pulse are controlled independently of each other. Thus, even though the sensor driving pulse and the motor drive pulse are out of good timing, each line of the image can be surely read.

Abstract: A reliable, low cost system for generating precisely aligned pixel clock and index signals for a digital scanning or printing system is based on the use of a phase locked loop multiplier to generate a sampling clock precisely synchronized to the drum position encoder sensor output. The sample clock frequency is chosen to be a large, known multiple M of the pixel clock frequency. The pixel clock is chosen to be the sample clock divided by M, making it the proper frequency. Pixel clock phase is established by resetting, on the trailing edge of an index signal generated by a line start index sensor, a .div.M counter used in deriving the pixel clock from the sample clock. The rising edge of the pixel clock is then established to within .+-.(1/M) pixel clock periods of the trailing edge of the index signal.

Abstract: An image signal processing device is arranged to convert an analog image signal into a digital image signal after the analog image signal is clamped, to separate, in the form of a digital signal, a synchronizing signal from the digital image signal and to control a clamping action on the analog image signal according to a state of the separated digital synchronizing signal. The arrangement enables the device to always stably perform the clamping action.

Abstract: A new and improved method and system for controlling the timing of a modulation input signal utilized for driving a laser engine of a laser or electrophotographic printer. This method and system utilizes a novel modulation generator circuit which operates to receive both a beam detect signal from the laser driver circuit and an asynchronous clock signal from the output of an asynchronous clock generator. The modulation generator in turn operates to delay the output signal from the asynchronous clock generator a predetermined number of times and then select the delayed clock signal which is closest in phase to the phase of the beam detect signal. Then this clock generated signal is used to set the modulation frequency of a bi-phase output digital clock signal from the modulation generator which is applied as input timing signal for video input data applied to laser driver circuit and used for developing images on a photoconductive drum.

Abstract: An image processing apparatus is provided with a counter counted up by the clock of a main CPU and reset by the clock of a subordinate CPU. If the value of the count recorded by the counter is not within a fixed range for a predetermined period of time, the apparatus is judged to have developed an abnormality and a power supply for driving components under the control of the subordinate CPU is turned off. Thus, current supplied by the power supply to such components as a recording motor, thermal head, reading motor, fluorescent lamp, stamping plunger and cutter motor is cut off. Thereafter, even if the apparatus returns to normalcy, the driving power supply for the components under the control of the subordinate CPU will not turn on until the main CPU issues a trigger signal.

Abstract: A video interface system can cope with a plurality of printers having different clock signal frequencies with reduced timing skew between image data and a clock signal. The video interface system interfaces an image data supplying apparatus, such as a host computer, with a printer. The video interface system comprises a reference clock signal sending unit, provided in the image data supplying apparatus, for sending back a reference clock signal supplied by the printer by means of a loop back control. A shift register is provided in the image data supplying apparatus, and sends image data to the printer in synchronization with the reference clock signal supplied by the printer.

Abstract: A video clock is supplied from the sync circuit of a controller. In response to this video clock, an external unit controller outputs image data supplied from a host unit. A delay amount between the video clock and the image data is determined by a phase correcting section, and the phase correcting section generates a corrected image area signal based on the delay amount. The delay amount of the video clock is corrected on the basis f the corrected image area signal. A printer engine forms an image on an image bearing member on a basis of the image data provided in response with the corrected video clock. In this manner, the video clock can be synchronized with the externally supplied image data with a simple arrangement without changing the video clock output to the external unit controller and adding a signal delay circuit.

Abstract: An image recording apparatus operated in synchronism with a vertical synchronization signal from an external device comprises a unit for sending out to the external device a signal indicating a status to accept the vertical synchronization signal, and switching device for switching between a plurality of operation modes related to an elapsed time from the send-out of the signal by the signal sending unit.

Abstract: An image reading apparatus has a sensing unit to repeat a scanning on an original image with a predetermined time interval between scans so as to obtain a new set of image information data with each scan, a memory unit to store the image information data and a control unit which commands the memory unit to read the image information stored therein. The memory unit has two memory areas, and each of the two memory areas is alternately updated with each scan for storing a set of the image information data. In response to a read command from the control unit, the memory unit starts to read the image information data from one of the memory areas which is not used for storing at the time the command is issued.

Abstract: An image reading system including a charge storing type image sensor drives a manuscript or an image sensor in accordance with a driving pulse from a driving unit. A speed of the driving pulse from the driving unit is determined by a speed setting unit, depending on a change of a period of the apparatus scan. The driving pulse is stopped for a certain period of time, so that the difference in a speed of the driving pulse between the different apparatus scan periods is decreased.

Abstract: In a data link control method, a receiver and a transmitter are connected so that the transmitter can transmit every line of a predetermined data at a first speed, the receiver plotting every line of the predetermined data on a recording paper thereof at a second speed. A predetermined mode is selected from either a buffer mode or a skip mode on the basis of a ratio of the first speed to the second speed and whether a buffer can be used by the receiver. The predetermined data is temporarily stored in the buffer and then plotted during the buffer mode. The recording paper of the receiver is fed at a third speed higher than a normal speed when a blank line of the predetermined data is plotted thereon during the buffer mode and skip mode.

Abstract: An image transmission apparatus comprises a color separating circuit for dividing a video image signal into color signals and a color burst signal, a sampling clock generating circuit for generating a clock signal having a frequency corresponding to a designated pixel number, and a sampling clock synchronizing circuit for converting the clock signal into a sampling clock signal synchronized with the color burst signal. A sampling frequency of a sampling unit (an A/D converter), which samples the color signals in accordance with the sampling clock signal to thereby produce sampled image data, is controlled in accordance with the sampling clock signal. The sampled image data are stored in a frame memory. The sampled image data stored in the frame memory are transmitted from an image data transmitting section composed of a static image compressing/expanding circuit and a transmitting/receiving section.

Abstract: An image formation device in which an image according to image data received from an image data output device is selectively written by light beam in an optical image memory and the image is printed out on a recording medium, includes a light source for emitting light beam, a scanning device for scanning a surface of the optical image memory with the light beam, a switch for turning on or off the light beam, a sensing device for sensing from the image data a beam irradiating period T per a single pixel corresponding to a density of the pixel, and a controller for controlling the switch so that the light beam intermittently performs T/n period irradiation n times during a scanning period per a single pixel.

Abstract: An image data compression transmission method performs coding of image data into coded data line by line, by a predetermined coding process, adding a synchronizing code to the coded data and generating coded information data by means of a coder. A decoder extracts the synchronizing code from the coded information data, and initializes a decoding process at the receiving side. The decoder determines the validity of the coded information data received from the coder based on the synchronizing code extracted therefrom.If the information data is invalid, then, the decoder performs error processing.

Abstract: The invention provides a synchronism establishing method and apparatus including a plurality of modules having different independent synchronization patterns to be switched wherein the switching transition process having a time length corresponding to the number of protection stages necessary for pull in and protection of synchronism is reduced so small that the presence of such switching transition process can be ignored while assuring similar advantages to those of conventional synchronism establishing apparatus. A master side module delivers a notification of establishment of synchronism thereof to a slave side module. When the slave side module is in a condition wherein synchronism is established, it puts its synchronizing operation into a waiting mode. Even if it thereafter detects a number of abnormal synchronization patterns greater than the number of protection stages, it does not determine a pull out condition and maintains the pulled in phase.

Abstract: The present invention is a clock signal apparatus for a document scanner that only produces a clock signal when pixel data is output. The apparatus includes a timing and control unit 94 that not only controls the sensor analog output process along with the conversion of the analog signals to digital data, but also provides a video clock signal only when the sensor data is present at the output of the scanner. The unit 94 also provides an intersensor period during which no pixel data is output and no clock signal is produced. The unit 94 supplies a horizontal synchronization signal before the video clock is started and a horizontal synchronization signal immediately after the last data is transmitted. The receiving unit 72 latches the data synchronous with the video clock signal. The video clock signal includes multiple edges allowing the various edges to control various stages of further processing of the sensor data.

Abstract: In an image reading apparatus, a signal generator generates a clock signal having a predetermined frequency, and generates a horizontal synchronizing signal in synchronous with the clock signal, and an image sensor reads a document image by scanning the document image in a main scan direction every horizontal scanning line in synchronous with the clock signal, and converts the read document image into an image signal. On the other hand, a stepping motor moves the image sensor and the document image relatively to each other in a subscan direction perpendicular to the main scan direction by one horizontal scanning line in synchronous with the clock signal. Further, a signal interface outputs the horizontal synchronizing signal and the image signal to an external apparatus. On the other hand, a receiver receives a stop request signal from the external apparatus.

Abstract: An image processing apparatus reading images by relatively moving linear CCDs in a subscanning direction on the original images includes a clock generation circuit for generating first and second clock signals having different pulse numbers per unit time, and first and second image memories alternately writing line by line the read image data, one of which carries out writing operation while the other carries out reading operation of the written image data. Writing address of the first and second image memory is designated by a first clock signal, and a reading address of the first and second image memory is designated by a second clock signal. When the image data is stored with low frequency clock signal and the image data are read in accordance with a high frequency clock signal, a reduced image can be formed.

Abstract: An image reading method for an image recording system which reads an image with an image reader in the form of photoelectric signal conversion devices, converts the resulting analog data into digital data, and prints out the digital data with a printer. One line of image is read a plurality of times by the image reader and the resulting image data are sequentially stored. Even when the image data storing time and a fixed one-line scanning period are different from each other, the image can be read and outputted without changing the quantity of light to be applied to the image reader, i.e., simply by compensating for the difference between the storing time and the fixed scanning time.

Abstract: An image communication apparatus having a mode to transmit image data with unity-magnification and a mode to transmit the image data with size reduction, comprises a selector for selecting one of the unity-magnification transmission mode and the reduced size transmission mode and a setter for setting one of different minimum transmission times in accordance with the mode selected by the selector.

Abstract: An imaging apparatus contains an image capture device having image capturing means and video encoding means, and an image printer. Electronic components in the image capture device produce image and timing signals. The image and timing signals bypass the video encoding means so that the printer does not internally require a video signal decoder. The signals received by the printer are slow speed signals which can be processed as received without need for an internal memory.

Abstract: A digital electronics system for generating pulses from a series of data words incluidng RAM lookup tables for translating the series of data words into a series of pulse attribute words, where each pulse attribute word includes information for controlling the formation of a corresponding pulse, multiplexers for splitting the series of pulse attribute words into two channels, pulse forming circuits corresponding to each channel for accepting pulse attribute words from respective channels and forming pulses using the information included in the pulse attribute words, and control circuits for generating the pulses, where a pulse from a first pulse forming circuit is generated while a pulse from a second pulse forming circuit is being formed.

Abstract: A document reading apparatus including a document reading unit for optically reading an image of a document, a document transfer unit for transferring the reading unit at a speed corresponding to the document reading density, and a pulse motor for driving the document transfer unit. The waveform of an exciting current supplied to the pulse motor is changed in accordance with the document reading density, and the pulse motor is rotated at a speed corresponding to the waveform of the exciting current.

Abstract: An image data communication system for controlling an image reader and an image recorder has an optical system for reading an image, a signal processor for processing the read image, microprocessors for controlling image reading and image data communication, and serial circuits for supplying control data. The system allows connection of image readers and image recorders of different types.The system also provides modes for transmitting status data from the image recorder in synchronism with either internally or externally generated clock pulses when the status data is requested by an external command or when an error occurs in an image recording operation.

Abstract: An image data communication system for controlling an image reader and an image recorder has an optical system for reading an image, a signal processor for processing the read image, microprocessors for controlling image reading and image data communication, and serial circuits for supplying control data. The system allows connection of image readers and image recorders of different types.

Abstract: An image forming apparatus includes an original document table for supporting an original document, an optical scanning device for scanning the original document supported by the original document table to capture an image of the original document and converting the captured image to an image data, an image forming unit for forming images on an image bearing medium according to the image data obtained by the optical scanning device, and a transmitter for transmitting a timing signal from the optical scanning device to the image forming unit. The timing signal represents a period of time required from the commencement of operation of the optical scanning device to the commencement of outputting the image data from the optical scanning device. The apparatus further includes a controller for controlling the formation of the images by synchronizing the operation of the image forming unit with the operation of the optical scanning device in response to the timing signal transmitted by the transmitter.

Abstract: The encoding method is adapted to the recognition of synchronization words in sequence of variable length encoded words, each encoded word corresponding to a specific message or event from a sequences of messages each assigned with a probability of occurrence. The method consists in constructing a dichotomizing encoding tree comprising a specific number of leaves (F1 . . . F4) distributed over priority levels (n.sub.1 . . . n.sub.4) classified in a decreasing order on processing from the root of the tree towards the leaves, the number of leaves being equal to the number of events to be encoded, in placing the leaves adjacent to one another on each level, the leaves corresponding to the most probable events being placed at one end to the right or to the left on each level, and in prohibiting, in the encoded words, the sequences of Smax bits of equal value, zero or one, in order to obtain an easy choice of synchronization words.

Abstract: A video signal processing circuit for a video printer operating to sample an analog video signal, to convert the video signal into digital data, to store the data in a memory, and to read out the contents of memory to a printer for printing. The circuit includes an oscillation circuit which generates a pixel clock in response to the horizontal sync signal in the video signal, a frequency division phase shift circuit which divides the frequency of the pixel clock provided by the oscillation circuit and shifts the frequency divided clock with the pixel clock, a selection circuit which selects one of frequency divided clocks having different phases provided by the frequency division phase shift circuit, and a selection control circuit which operates on the selection circuit to alter the clock selection at each arrival of vertical sync signal, so that the sampling of the video signal is implemented in response to the clock output of the selection control circuit.

Abstract: A driving system for a stepping motor wherein the stepping motor is rotated by a predetermined angle for each driving step. The system counts the time between two successive driving triggers, and changes at least one of the phase energization current and the phase energization time at the start of the driving of the stepping motor in response to the time count.

Abstract: A driving system for driving a stepping motor to which the number of driving steps and a driving trigger are input to rotate the stepping motor by a half step so as to follow a one-two phase energization sequence. The system energizes one phase of the motor by a driving mode command to position a rotor, and the motor is then rotated by starting energization from two phases next to the one phase already energized.

Abstract: A recording apparatus is provided with detecting means for detecting any abnormality of a synchronizing signal included in an incoming signal; processing means for processing the incoming signal into a print recording signal; and print recording means for carrying out print recording in accordance with the print recording signal. Erroneous recording is prevented by inhibiting the print recording signal from being supplied to the print recording means when any abnormality is detected in the synchronizing signal.

Abstract: The object of the present invention is to provide an image forming apparatus capable of enabling high-speed continuous copy of an same single-color image, wherein the apparatus is incorporated with a shift register between an image reader and a laser beam generated for performing imagewise exposure onto a photoreceptor. The shift register has a circulation circuit connecting between an output and an input side thereof. After an image data corresponding to a sheet of original document is inputted into the shift register, the circulation circuit is actuated and circulates the image data, thereby repeatedly outputting the image data to the laser beam generator by the number of required times.

Abstract: Disclosed is a synchronizing circuit for an optical scanning apparatus in which synchronization of writing of an image in the horizontal direction is achieved using a synchronizing signal generated in response to the output signal of an photo sensor for detecting the light which has passed through a scanning means. The synchronizing circuit includes a frequency dividing circuit for dividing the frequency of a clock pulse train having a predetermined frequency in response to the output signal from the photo sensor, a delay circuit for successively delaying the phase of the frequency divided clock pulse train by a predetermined time interval when it produces output signals, and a selecting circuit for selecting as a synchronizing signal the output of the delay circuit whose phase difference is at a minimum with respect to the output of the photo sensor.

Abstract: Apparatus for recording a displayed frame of video data by storing the binary data bits from identical segments of each video scan line, thereafter supplying the stored bits of the segments to a traversing matrix print head for recording the bits in those segments, and repeating the process with data bits from a different series of scan line segments. The number of data bits comprising a segment usually corresponds to the number of recording elements in the print head, and the number of print head excursions will vary inversely to the number of data bits in each segment. A resulting recorded video frame thus appears rotated 90.degree. with respect to the original frame orientation.

Abstract: A clock signal generation apparatus is disclosed in which an original signal source generates an original clock signal, a first frequency divider starts dividing the frequency of the original clock signal in response to the rise of the original clock signal and produces a frequency-divided clock signal, a second frequency divider starts dividing the frequency of the original clock signal in response to the fall of the original clock signal and produces a frequency-divided clock signal, a sync timing signal source generates a sync timing signal, and a selection circuit renders effective selected one of the first and second frequency dividers in accordance with a level of the original clock signal at selected one of the ride and fall timings of the sync timing signal thereby to produce the frequency-divided clock signal of the effective frequency divider as a clock signal.

Abstract: A time adjusting system includes a facsimile machine having a real time clock and a center station in charge of management of accurate time information. The facsimile machine places a call to the center station at a predetermined time and receives accurate time information therefrom to thereby adjust the time of its own real time clock.