GB1564355A

GB1564355A - Document copying apparatus

Info

Publication number: GB1564355A
Application number: GB5216276A
Authority: GB
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1976-12-14
Filing date: 1976-12-14
Publication date: 1980-04-10
Also published as: DE2754145C2; JPS5374434A; NL7713247A; BR7708264A; DE2754145A1

Description

(54) DOCUMENT COPYING APPARATUS (71) We, XEROX CORPORATION of Rochester, New York State, United States of America, a Body Corporate organized under the laws of the State of New York, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to the testing of document copying machines.

Modern document copying machines are complicated in nature, and require the attendance of skilled engineers to make all but the most simple adjustments. The usual operator is not a skilled engineer and is not able or encouraged to adjust the apparatus, and any such attempts at adjustment may result in damage being done to to the apparatus. On the other hand, the time taken for an engineer to travel to and from the apparatus may be very large compared with the time taken for him to make the necessary adjustment.

Some attempts have been made to provide some form of control in document copying apparatus without the intervention of an operator or an engineer. United States Specification 3,094,049 describes how toner is cascaded over a pair of transparent electrodes held at a given potential difference, and the density of toner which is attracted to the electrodes is sensed photoelectrically to control toner replenishment apparatus. With this arrangement, it is not necessary for the operator to watch the density of the copies made by the apparatus and to replenish the toner when he considers the density is too low.

In U.S. 3,094,049, the electrodes on which the toner is deposited and its density sensed are separate from the photosensitive drum of the machine. The control toner image may be deposited on the drum itself, as dislosed in United States Specifications 3,348,521, 3,348,523, and 3,801,196. The density of the control toner deposit on the drum is still photoelectrically sensed, and the control toner image is located on an edge portion of the drum so that although the control toner image is developed by the same developing apparatus as the document image on the drum, the transfer station at which the document image is transferred to a copy sheet does not extend to the control toner image, and the control toner image is not transferred to a copy sheet.

It was mentioned above that U.S.

3,094,049 avoided the need for the operator to check the density of the copies made by the apparatus. It is often preferable that the machine performance should be assessed at a central control location, for example the offices of the servicing organisation for the apparatus, and the present invention is concerned with the production of a suitable copy which can be despatched to the central control location. The invention is concerned with the performance of the apparatus in general, and particularly with those features of the apparatus which cannot be automatically controlled such as the toner replenishment mentioned above, but which require the attendance of an engineer.It is more reliable for the machine performance to be assessed at the central control location by relatively skilled personnel and an engineer visit arranged, rather than for the machine performance to be assessed by a relatively inexperienced operator who might summon an engineer unnecessarily.

According to the present invention there is provided a document copying apparatus comprising an image receiving surface for receiving a latent electrostatic image, means for developing said latent electrostatic image, and means for transferring said developed image to a copy sheet, to gether with a selectively operable transducer responsive to an aspect of the performance of the apparatus to cause said latent electrostatic image to represent said aspect, so that the resultant copy includes an indication of said aspect of the performance of the apparatus.

The information from the transducer may be copied in conjunction with a master document, the master document including details of the client and the apparatus, the latent image being formed by exposure of the image receiving surface while charged to an image of the master document, the transducer causing exposure of a portion of the image receiving surface which is not discharged by the image of the master document. The transducer could be arranged to discharge a portion of the image receiving surface alongside the image of the master document, or a portion within the image of the master document which corresponds to a dark portion of the masster document (which does not therefore cause discharge of the image receiving surface).The resulting document will thus produce a record of the client and the machine together with the information representative of the performance of the apparatus.

Preferably, a plurality of aspects of the performance of the apparatus will be represented by the transducer for representation on the resultant copy. One such aspect may be the rate of performance, i.e.

the number of copies made for use in billing the client when the charge to the client is determined by the number of copies made.

The transducer is selectively operable since the user of the apparatus will not wish details of the performance of the apparatus to appear on his normal copies.

It is convenient to store the master document within the machine, and to draw the master document into position for copying by the machine in synchronism with the operation of the transducer so that the information concerning the performance of the apparatus is copied onto the master document and then the machine is returned for normal use with the user's own documents and without details of the performance of the apparatus being copied.

This operation could for example be performed by the operator once a month to provide billing information and other details of the machine performance, the resultant copy being despatched to the central control location. At the central control location, the information can be sensed by machine or by personnel, the billing information being converted into an invoice to the client, and the other performance information being transmitted to and engineer to arrange any visits which may be necessary to service the machine. The style of the information representing the performance of the apparatus should be suitable for sensing at the control location, and might be in the form of a binary code represented in conjunction with the master document on the resultant copy, or a series of alphanumeric symbols.

The performance of copying apparatus is often tested by means of a test card containing lines of various separations to test machine resolution and areas of different density to test machine contrast and development density. Elements of such test cards can be included on the master document, so that the resultant copy shows how the machine has coped with such resolution and density tests. The resultant copies may be assessed in the central control location, or may be sensed from the developed image either before or after transfer to the copy sheet within the apparatus to provide an immediate control of components in the apparatus, in a similar way to the earlier toner control systems described above.The inclusion of the test card elements in the resultant copy which is despatched to the central control location provides a permanent record of such testing, although the apparatus should make its own adjustment automatically, and the engineer can simply test that the adjustments have been made during his next visit.

An example of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 shows a document reproduction machine, and Figure 2 shows a master document for use with the machine of Figure 1.

As in all electrostatic reproduction machines of the type illustrated in Figure 1, a light image of an original is projected onto the photosensitive surface of a xerographic plate to form an electrostatic latent image thereon. Thereafter, the latent image is developed with material comprising carrier beads and oppositely charged toner particles triboelectrically adhering thereto to form a xerographic powder image corresponding to the latent image on the photosensitive surface. The powder image is then electrostatically transferred to a transfer member such as a sheet of paper to which it may be fixed by a fusing device whereby the toner image is caused permanently to adhere to the transfer member.

In the illustrated machine 10, an original 12 to be copied is placed upon a transparent support platen 14 fixedly arranged in an illumination assembly indicated generally by the reference numeral 16. While upon the platen, the illumination assembly flashes light rays upon the original, thereby producing image rays corresponging to the informational areas on the original. The image rays are projected by means of an optical system 18 to an exposure station 20 for exposing the surface of a moving xerographic plate in the form of a flexible photoconductive belt or photoreceptor 22.

In moving in the direction indicated by the arrow, prior to reaching the exposure station 20, that portion of the belt being exposed would have been uniformly charged to approximately +900 volts (in the present example) by a corona generating device 24 located at a belt run extending between the belt supporting rollers 26 and 28. The exposure station extends between the roller 28 and a third roller 30.

The exposure of the photosensitive surface of the belt to the light image discharges the surface in the areas struck by light whereby an electrostatic latent image remains on the belt in image configuration corresponding to the dark area of the light image projected from the original on the support platen. As the belt continues its movement, the latent image passes a predevelopment corona generating device (not shown), around the roller 30, and through a developing station 32 where a developing apparatus indicated generally by the reference numeral 34 is positioned. The predevelopment corona generating device 31 conditions the image prior to development as will be more fully explained below. The developing apparatus 34 comprises a plurality of magnetic brushes 36 which carry developing material to the surface of the upwardly moving belt 22.As the developing material is applied to the belt, toner particles in the development material are electrostatically attracted to the charged photosensitive surface to form a powder image (an electrostatic developed image).

The developed electrostatic image is trans Dorted by the belt 22 to a transfer station 38 where a sheet of paper is moved at a speed in syncronism with the moving belt in order to effect transfer of the developed image. Located at the transfer station 38 is a transfer roll 40 which is arranged on the frame of the machine to contact the back side of the sheet of paper as the latter is moved or fed between the belt and the transfer roll. The roll 40 is electrically biased with sufficient voltage so that the developed image on the belt may be electrostatically attracted to the adjacent side of a sheet of paper as the latter is brought into contact therewith. The transfer roll 40 applies a charge to the entire sheet as it moves between the roll and the belt 22.

A suitable sheet transport mechanism transports sheets of paper seriatim from a paper handling mechanism indicated generally by the reference numeral 42 to the developed image on the belt as the same is carried around the roller 26. In passing from the paper handling mechanism to the transfer roll 40, each sheet contacts a plurality of registration fingers 44.

As a sheet emerges from the transfer station 38, a charge is deposited thereon by a detack corona generating device 46 to lessen the electrostatic attraction between the belt 22 and the sheet so that the latter can be removed by a vacuum stripping and transport mechanism 48. The sheet is thereafter retained on the underside of the vacuum stripping transport mechanism 48 for movement into a fuser assembly indicated generally by the reference numeral 50 wherein the powder image on the sheet is permanently affixed therto. After fusing, the finished copy is discharged at a suitable point for collection. The toner particles remaning as residue on the belt 22 are carried by the belt to a cleaning apparatus 52.

The cleaning apparatus 52 comprises a corona discharge device 54 for neutralizing charges remaining on the untransfered toner particles, a rotating brush 56 mounted within a housing 58, and a vacuum outlet 60.

Figure 2 shows a master document suitable for use with the apparatus of Figure 1. This document is stored within the machine, to avoid danger of becoming lost or damaged, on a roller 61 and is drawn across the under-surface of the platen 14 automatically when the machine is programed to carry out its test mode, into the position shown at 62 in Figure 1. The position 62 lies within the focal limits of the projection system 18, so that an image of the master document is projected onto the belt 22.

As shown in Figure 2, the master document contains details of the client at 63, and of the machine at 64, and also contains a pre-paid address label 65 so that the copy of the master document can be folded and sent through the post to the offices of the billing and servicing organization.

Across the centre of the master document is a dark area 66, which does not cause substantial discharge of the photoreceptor 22 when its image is projected by the projection system 18. The master document also contains a test area 67, comprising elements of a test card, for testing the resolution and development density of the apparatus.

The copier apparatus contains transducers 71 which respond to various aspects of the performance of the coping machine, the transducers 71 being connected to a lightemitting device 72 adjacent the photoreceptor 22 between the charging device 24 and the roller 28. The light-emitting device, which is conveniently a light-emitting diode, can be located anywhere between the charging device 24 in the direction of movement of the photoreceptor 22 to the developing station 32. When the apparatus is operated in the test mode, the master document is moved to the position 62 as described above, and the transducers 71 are caused to provide signals to actuate the light-emitting diode 72, so as selectively to discharge the area on the belt 22 corresponding to the position of the dark area 66 in the latent image formed of the master document.The resultant copy will therefore contain a coded image representative of the machine performance. This coded image may be in any convenient form of representation, for example binary code or alphanumeric symbols, and the light-emitting device 72 is adapted to provide the most convenient form of representation. It might be convenient to adapt the latent image of the master document by means of a charging device in place of the ligtht-emitting device 72 in response to the output of the transducers 71.

The apparatus is also provided with a sensing device 73 responsive to the developed image of the test area 67 on the master document. The detector 73 is connected to adjustable portions of the apparatus, for example the replenishment device of the developing apparatus 34 so as to adjust these components in response to the form of the image of the test area 67. The techniques disclosed in United States Patent Specifications 3,348,521, 3,348,523 and 3,801,196 may be utilized. The detector 73 can be located anywhere in the path of the developed image from the developing station 32 through the fuser 50 to the output tray of the apparatus shown at 74.

After the machine has made the required number of copies of the master document, the apparatus is returned to its normal copying mode, the master document being re-rolled on the roller 61, and the device 72 and detector 73 being inactivated. The apparatus can then return to its normal copying procedure until the time comes to repeat the test mode. One copy of the master document produced by the machine during the test mode is folded to form a postal item with the copy of the address label 65 visible, and is sent to the offices of the billing and servicng organzation. The billing informaton provded by the transducer 71 is used to prepare an invoice for the user of the apparatus, and the information as to the performance of the apparatus from the transducer 71 is assessed by the servicing organization and a visit of an engineer is arranged where necessary.

It may be convenient for orders for stationery to be included on the copy of the master document which is despatched, so that stationery supplies for the apparatus can be maintained.

WHAT WE CLAIM IS: 1. Document copying apparatus comprising an image receiving surface for receiving a latent electrostatic image, means for developing said latent electrostatic image, and means for transferring said developed image to a copy sheet, together with a selectively operable transducer responsive to an aspect of the performance of the apparatus to cause said latent electrostatic image to represent said aspect, so that the resultant copy includes an indication of said aspect of the performance of the apparatus.

2. Apparatus as claimed in claim 1 comprising means to store a master document within the apparatus, means to move said master document into a position to be copied on to the image receiving surface, the latent electrostatic image formed on exposure of the master document containing in response to the operation of the transducer a representation of said aspect of the performance of the apparatus, the means to move the master document being operable together with means to activate said transducer.

3. Apparatus as claimed in claim 2 comprising means responsive to the image of a test area which is located on said master document to control a component of the apparatus.

4. Apparatus as claimed in claim 3 wherein said means responsive to the image of the test area is actuated simultaneously with said means to move the master document and said transducer.

5. Apparatus as claimed in any one of the preceding claims wherein said means to cause said latent electrostatic image to represent said aspect comprises a lightemitting diode responsive to said transducer.

6. Document copyng apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. can be located anywhere between the charging device 24 in the direction of movement of the photoreceptor 22 to the developing station 32. When the apparatus is operated in the test mode, the master document is moved to the position 62 as described above, and the transducers 71 are caused to provide signals to actuate the light-emitting diode 72, so as selectively to discharge the area on the belt 22 corresponding to the position of the dark area 66 in the latent image formed of the master document. The resultant copy will therefore contain a coded image representative of the machine performance. This coded image may be in any convenient form of representation, for example binary code or alphanumeric symbols, and the light-emitting device 72 is adapted to provide the most convenient form of representation.It might be convenient to adapt the latent image of the master document by means of a charging device in place of the ligtht-emitting device 72 in response to the output of the transducers 71. The apparatus is also provided with a sensing device 73 responsive to the developed image of the test area 67 on the master document. The detector 73 is connected to adjustable portions of the apparatus, for example the replenishment device of the developing apparatus 34 so as to adjust these components in response to the form of the image of the test area 67. The techniques disclosed in United States Patent Specifications 3,348,521, 3,348,523 and 3,801,196 may be utilized. The detector 73 can be located anywhere in the path of the developed image from the developing station 32 through the fuser 50 to the output tray of the apparatus shown at 74. After the machine has made the required number of copies of the master document, the apparatus is returned to its normal copying mode, the master document being re-rolled on the roller 61, and the device 72 and detector 73 being inactivated. The apparatus can then return to its normal copying procedure until the time comes to repeat the test mode. One copy of the master document produced by the machine during the test mode is folded to form a postal item with the copy of the address label 65 visible, and is sent to the offices of the billing and servicng organzation. The billing informaton provded by the transducer 71 is used to prepare an invoice for the user of the apparatus, and the information as to the performance of the apparatus from the transducer 71 is assessed by the servicing organization and a visit of an engineer is arranged where necessary. It may be convenient for orders for stationery to be included on the copy of the master document which is despatched, so that stationery supplies for the apparatus can be maintained. WHAT WE CLAIM IS:

1. Document copying apparatus comprising an image receiving surface for receiving a latent electrostatic image, means for developing said latent electrostatic image, and means for transferring said developed image to a copy sheet, together with a selectively operable transducer responsive to an aspect of the performance of the apparatus to cause said latent electrostatic image to represent said aspect, so that the resultant copy includes an indication of said aspect of the performance of the apparatus.