Claims
- 1. An improved electrophotographic reproducing machine of the type having a fixed platen for stationarily supporting an original document to be reproduced, a photoconductive belt having a photoconductive surface on one side thereof, means for charging the photoconductive belt surface with an uniform charge, means for incrementally scanning the original document on the fixed platen one segment at a time and concurrently exposing the uniformly charged photoconductive belt surface to the scanned image segments to record an electrostatic latent image of the original document on said photoconductive belt surface one segment at a time, and means for transferring the electrostatic latent image to a dielectric copy sheet, wherein the improvement comprises:
- a translatable carriage having fixedly mounted thereon in fixed relationship to each other the charging means, the scanning and exposing means, the transfer means, and a roller about which the photoconductive belt is entrained, the roller having an axis parallel to the fixed platen;
- means to translate the carriage in a direction parallel to the fixed platen and perpendicular to the roller axis to effect the incremental scanning of the original document and concurrent recording thereof on the photoconductive belt surface and in the oppposite direction to return the carriage for scanning the same document again or a subsequent document placed on the fixed platen; and
- the photoconductive belt having two ends and being entrained about the carriage roller at a location intermediate the ends, means for holding one end of the photoconductive belt stationary at least during the recording of the electrostatic latent image thereon, the other end of the photoconductive belt being attached to a fixedly positioned take-up roll adapted to take up the slack of the photoconductive belt and keep it taut about the carriage roller as the carriage moves in a scanning direction or to dispense the photoconductive belt as the carriage moves in the opposite direction to return the carriage for subsequet document scanning, the photoconductive belt surface confronting the fixed platen and being held stationarily parallel thereto prior to and during the recording thereon of the electrostatic latent image segments, whereupon the carriage translating means moves the carriage, so that the portion of the photoconductive belt surface having the recorded latent image segments travels around the carriage roller towards the transfer means and take-up roller, while the unrecorded portion of the photoconductive belt is held stationary.
- 2. The improved reproducing machine of claim 1, wherein the charging means is located upstream of the scanning and exposing means to charge the belt photoconductive belt surface prior to the recording thereon of the electrostatic latent image segments.
- 3. The improved reproducing machine of claim 2, wherein the scanning and exposing means is a lamp and a lens strip combination mounted on said carriage in fixed relationship to each other and the carriage roller.
- 4. The improved reproducing machine of claim 3, wherein the improvement further comprises:
- means for moving seriatim dielectric copy sheets into lineal contact with the photoconductive belt on the carriage roller and at the location of the transfer means, the copy sheets each moving in the same direction as the translating carriage, one copy sheet being moved for each original document scanned, the moving velocity of the copy sheet being twice that of the linear velocity of the carriage roller, so that the relative velocity between the photoconductive surface of the belt and the copy sheet at the point of contact is zero enabling the electrostatic latent image segments to be transferred to the copy sheets incrementally by the transfer means, whereby after the electrostatic latent image has been transferred to the copy sheet, it does not have to be shielded from light;
- means for advancing the copy sheet with the electrostatic latent image to a development station, whereat the electrostatic latent image is developed with development particles; and
- means for conveying the copy sheets with the developed images to a fixing station, whereat the developed image are permanently fixed to said copy sheet.
- 5. The improved reproducing machine of claim 3, wherein the means for holding one end of the photoconductive belt stationary comprises securing one end of the photoconductive belt to a stationary frame member of the reproducing machine.
- 6. The improved reproducing machine of claim 3, wherein the means for holding one end of the photoconductive belt sationary comprises a supply spool from which a length of photoconductive belt is periodically dispensed to replace a damaged or worn belt length, and between periodic dispensing of photoconductive belt lengths, the supply spool fixedly secures one end of the photoconductive belt.
Parent Case Info
This is a continuation of application Ser. No. 126,586 filed Mar. 3, 1980, now abandoned.
This invention relates generally to a reproducing machine, and more particularly concerns an electrophotographic printing machine having a stationary photoconductive member and a stationary original document.
The process of electrostatographic printing requires the formation and utilization of an electrostatic latent image for the purpose of recording and reproducing patterns in viewable form. Electrostatographic printing includes electrophotographic printing and electrographic printing. In electrophotographic printing, electromagnetic radiation is used to form an electrostatic latent image on a photoconductive member. An electrographic printing machine employs an insulating medium to form, without the aid of electromagnetic radiation, an electrostatic latent image. Generally, the process of electrophotographic printing includes charging a photoconductive member to a substantially uniform potential to sensitize the surface thereof. The charged portion of the photoconductive surface is exposed to a light image of an original document being reproduced. This records an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document being reproduced. After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed by bringing particles of a developer mix into contact therewith. The developer mix particles are attracted to the latent image forming a particle image on the photoconductive member. The particle image is then transferred from the photoconductive member to a copy sheet. Finally, the copy sheet is heated to permanently affix the particles thereto in image configuration. This general approach was disclosed by Carlson in U.S. Pat. No. 2,297,691 and has been further amplified and described in many related patents in the art.
In electrophotographic printing, the electrostatic latent image comprises electrostatic surface charges. These surface charges may be transferred to or reproduced upon a dielectric surface. The technique for accomplishing charge transfer is referred to as a TESI process, for transfer of electrostatic latent images. Hence, electrostatic latent images may be transferred to another surface prior to development. The material to which the electrostatic latent image is transferred must, of course, be capable of retaining the image, i.e. it must be a good insulator. Thus, electrostatic latent images may be transferred to the dielectric coated paper. The transferred images can be developed by the same methods hereinbefore described for developing the electrostatic latent images recorded on the photoconductive member. However, since the charge on the dielectric surface is not dissipated by exposure to light, it is not necessary to shield the image from light during development. After the electrostatic latent image transferred to the dielectric sheet has been developed, the powder image thereon may be fused thereto forming a finished copy sheet.
Various types of electrostatographic printing machines have hereinbefore been employed to utilize the foregoing processes. The following disclosures appear to be relevant:
The relevant portions of the foregoing disclosures may be briefly summarized as follows:
The Walkup patents disclose a photosensitive plate closely spaced to an electrode with an insulating web passing therebetween. Voltage is induced between the plate and electrode to cause the electrical charge pattern recorded on the plate to migrate to the web. The web is developed and the resultant powder image fused thereto so as to form a copy of the original document.
Fotland et al. describes the formation of an electrostatic latent image on a photosensitive element. The photosensitive element is brought into contact with a plate consisting of an electrically insulating material and an electrically conductive material. Electrical contact is established between the conductive layer of the photosensitive element and the conductive material of the plate. As a result, the latent image is transferred to the insulating material of the plate which is developed into a visible image.
Carlson et al. teaches the transfer of an electrostatic latent image which has been previously formed on a first insulating surface to a second insulating surface in contact therewith by producing an intense electrical field between the surface and subsequently separating the surfaces.
Mix, Jr. describes a photoconductive drum moving in a planetary motion so that a point on the drum's surface has zero velocity when adjacent to a particular functional station. This permits incremental printing upon the paper. This movement of the drum permits the paper to be moved freely between printing stations.
In accordance with the features of the present invention, there is provided a reproducing machine including means for supporting substantially stationarily an original document being reproduced and a photoconductive member. Means to record the latent image on the photoconductive member. Means are provided for translating the photoconductive member with the portion of the photoconductive member in communication with the recording means being substantially stationary relative to the original document being reproduced.
US Referenced Citations (5)
Continuations (1)
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Number |
Date |
Country |
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126586 |
Mar 1980 |
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Patent Grant
4610526
